I have the same issue as with LineageOS 16: trying to fetch or send a MMS causes the phone to lose the data connectivity until I turn data off and on again (or airplane mode):
05-06 02:25:09.780 2744 3939 V Transaction: sending mms
05-06 02:25:09.814 731 1040 D MmsServiceBroker: sendMessage() by foundation.e.message
05-06 02:25:09.781 2744 3939 V Transaction: sending mms
05-06 02:25:09.821 1167 1387 D MmsService: sendMessage
05-06 02:25:09.827 1167 1387 D MmsService: Current running=0, current subId=-1, pending=0
05-06 02:25:09.827 1167 1387 D MmsService: Add request to running queue for subId 1
05-06 02:25:09.829 1167 3079 I MmsService: [SendRequest@859b11c] Executing...
05-06 02:25:09.829 1167 3079 I MmsService: mms config for sub 1: Bundle[{httpSocketTimeout=60000, aliasMinChars=2, smsToMmsTextThreshold=-1, enableSMSDeliveryReports=true, maxMessageTextSiz
e=-1, supportMmsContentDisposition=true, enabledTransID=false, aliasEnabled=false, supportHttpCharsetHeader=false, allowAttachAudio=true, smsToMmsTextLengthThreshold=-1, recipientLimit=214748
3647, uaProfTagName=x-wap-profile, aliasMaxChars=48, maxImageHeight=1944, enableMMSDeliveryReports=false, userAgent=, mmsCloseConnection=false, config_cellBroadcastAppLinks=true, maxSubjectLe
ngth=40, httpParams=, enableGroupMms=true, emailGatewayNumber=, maxMessageSize=614400, naiSuffix=, enableMMSReadReports=false, maxImageWidth=2592, uaProfUrl=, enabledMMS=true, enabledNotifyWa
pMMSC=false, sendMultipartSmsAsSeparateMessages=false, sim_country_iso_override_string=, enableMultipartSMS=true}]
05-06 02:25:09.836 1167 3079 D MmsService: [SendRequest@859b11c] MmsNetworkManager: start new network request
05-06 02:25:09.837 731 1130 D ConnectivityService: requestNetwork for uid/pid:1001/1167 NetworkRequest [ REQUEST id=50, [ Transports: CELLULAR Capabilities: MMS&NOT_RESTRICTED&TRUSTED&NOT_
VPN Unwanted: Specifier: <1> Uid: 1001] ]
05-06 02:25:09.838 731 853 D ConnectivityService: rematching NetworkAgentInfo [MOBILE (LTE) - 128]
05-06 02:25:09.838 731 853 D ConnectivityService: network has: [ Transports: CELLULAR Capabilities: SUPL&DUN&FOTA&INTERNET&NOT_RESTRICTED&TRUSTED&NOT_VPN&VALIDATED&NOT_ROAMING&FOREGROUND
&NOT_CONGESTED&NOT_SUSPENDED Unwanted: LinkUpBandwidth>=51200Kbps LinkDnBandwidth>=102400Kbps Specifier: <1>]
05-06 02:25:09.838 731 853 D ConnectivityService: Network NetworkAgentInfo [MOBILE (LTE) - 128] was already satisfying request 2. No change.
05-06 02:25:09.838 731 853 D ConnectivityService: Network NetworkAgentInfo [MOBILE (LTE) - 128] was already satisfying request 38. No change.
05-06 02:25:09.838 731 853 D ConnectivityService: checking if request is satisfied: NetworkRequest [ REQUEST id=50, [ Transports: CELLULAR Capabilities: MMS&NOT_RESTRICTED&TRUSTED&NOT_V
PN Unwanted: Specifier: <1> Uid: 1001] ]
05-06 02:25:09.838 731 853 D ConnectivityService: Network NetworkAgentInfo [MOBILE (LTE) - 128] was already satisfying request 40. No change.
05-06 02:25:09.838 731 853 D ConnectivityService: Network NetworkAgentInfo [MOBILE (LTE) - 128] was already satisfying request 42. No change.
05-06 02:25:09.838 731 853 D ConnectivityService: Network NetworkAgentInfo [MOBILE (LTE) - 128] was already satisfying request 10. No change.
05-06 02:25:09.838 731 853 D ConnectivityService: Network NetworkAgentInfo [MOBILE (LTE) - 128] was already satisfying request 1. No change.
05-06 02:25:09.838 731 853 D ConnectivityService: Network NetworkAgentInfo [MOBILE (LTE) - 128] was already satisfying request 7. No change.
05-06 02:25:09.839 731 853 D ConnectivityService: Network NetworkAgentInfo [MOBILE (LTE) - 128] was already satisfying request 16. No change.
05-06 02:25:09.839 731 853 D ConnectivityService: sending new Min Network Score(0): NetworkRequest [ REQUEST id=50, [ Transports: CELLULAR Capabilities: MMS&NOT_RESTRICTED&TRUSTED&NOT_VPN
Unwanted: Specifier: <1> Uid: 1001] ]
05-06 02:25:09.839 731 888 I chatty : uid=1000(system) EthernetService expire 3 lines
05-06 02:25:09.840 1167 1167 D PhoneSwitcherNetworkRequstListener: got request NetworkRequest [ REQUEST id=50, [ Transports: CELLULAR Capabilities: MMS&NOT_RESTRICTED&TRUSTED&NOT_VPN Unwant
ed: Specifier: <1> Uid: 1001] ] with score 0
05-06 02:25:09.848 1167 1167 D TelephonyProvider: subIdString = 1 subId = 1
05-06 02:25:09.850 2744 3941 E CursorToMessage$Message: Couldn't find column 'err_type' in [_id, thread_id, date, date_sent, msg_box, read, m_id, sub, sub_cs, ct_t, ct_l, exp, m_cls, m_type
, v, m_size, pri, rr, rpt_a, resp_st, st, tr_id, retr_st, retr_txt, retr_txt_cs, read_status, ct_cls, resp_txt, d_tm, d_rpt, locked, sub_id, seen, creator, text_only]
05-06 02:25:09.851 2744 3941 E CursorToMessage$Message: Couldn't find column 'err_type' in [_id, thread_id, date, date_sent, msg_box, read, m_id, sub, sub_cs, ct_t, ct_l, exp, m_cls, m_type
, v, m_size, pri, rr, rpt_a, resp_st, st, tr_id, retr_st, retr_txt, retr_txt_cs, read_status, ct_cls, resp_txt, d_tm, d_rpt, locked, sub_id, seen, creator, text_only]
05-06 02:25:09.903 731 1098 I chatty : uid=1000(system) Binder:731_6 expire 6 lines
05-06 02:25:09.951 731 1098 D ConnectivityService: registerNetworkAgent NetworkAgentInfo{ ni{[type: MOBILE[LTE], state: CONNECTED/CONNECTED, reason: connected, extra: sl2sfr, failover: fal
se, available: true, roaming: false]} network{129} nethandle{557456478221} lp{{InterfaceName: rmnet0 LinkAddresses: [100.106.102.135/32,] Routes: [0.0.0.0/0 -> 100.106.102.136 rmnet0,100.
106.102.135/32 -> 0.0.0.0 rmnet0,] DnsAddresses: [172.20.2.39,172.20.2.10,] UsePrivateDns: false PrivateDnsServerName: null Domains: null MTU: 1500 TcpBufferSizes: 524288,1048576,8388608,2621
44,524288,4194304}} nc{[ Transports: CELLULAR Capabilities: MMS&NOT_RESTRICTED&TRUSTED&NOT_VPN&NOT_ROAMING&FOREGROUND&NOT_CONGESTED&NOT_SUSPENDED Unwanted: LinkUpBandwidth>=51200Kbps LinkDn
Bandwidth>=102400Kbps Specifier: <1>]} Score{10} everValidated{false} lastValidated{false} created{false} lingering{false} explicitlySelected{false} acceptUnvalidated{false} everCaptivePo
rtalDetected{false} lastCaptivePortalDetected{false} clat{null} }
05-06 02:25:09.953 731 853 D ConnectivityService: Got NetworkAgent Messenger
05-06 02:25:09.954 731 853 D ConnectivityService: NetworkAgentInfo [MOBILE (LTE) - 129] EVENT_NETWORK_INFO_CHANGED, going from null to CONNECTED
05-06 02:25:09.955 257 298 D TcpSocketMonitor: resuming tcpinfo polling (interval=30000ms)
05-06 02:25:09.957 731 853 D ConnectivityService: Adding iface rmnet0 to network 129
05-06 02:25:09.958 257 298 E Netd : interface rmnet0 already assigned to netId 128
05-06 02:25:09.959 731 853 E ConnectivityService: Exception adding interface: java.lang.IllegalStateException: command '324 network interface add 129 rmnet0' failed with '400 324 addInter
faceToNetwork() failed (Device or resource busy)'
05-06 02:25:09.959 731 853 D ConnectivityService: Setting MTU size: rmnet0, 1500
05-06 02:25:09.960 731 853 D ConnectivityService: Adding Route [100.106.102.135/32 -> 0.0.0.0 rmnet0] to network 129
05-06 02:25:09.961 257 298 E Netd : interface rmnet0 assigned to netId 128, not 129
05-06 02:25:09.962 731 853 E ConnectivityService: Exception in addRoute for non-gateway: java.lang.IllegalStateException: command '326 network route add 129 rmnet0 100.106.102.135/32' fai
led with '400 326 addRoute() failed (No such file or directory)' 05-06 02:25:09.962 731 853 D ConnectivityService: Adding Route [0.0.0.0/0 -> 100.106.102.136 rmnet0] to network 129
05-06 02:25:09.965 731 853 E ConnectivityService: Exception in addRoute for gateway: java.lang.IllegalStateException: command '327 network route add 129 rmnet0 0.0.0.0/0 100.106.102.136'
failed with '400 327 addRoute() failed (No such file or directory)'