Dual SIM results in no/limited mobile data on Teracube 2e (2020 batch)

ahoy all,

when putting 2 SIMs in the dual slots of a Teracube 2e (first i.e. 2020 batch) with only one SIM selected for mobile data, mobile data does not work … or more specifically works only very very briefly (~3-4 seconds) every ~15 seconds. i can see the LTE sign showing briefly next to the reception bars when the mobile data actually works, and some apps will receive a tiny sliver of data. i tried various solutions found online, including Using /e/ with two sim cards: How to switch mobile data?, but no luck yet.

my particular setup is as follows: i am in Italia with a T-Mobile USA SIM in slot #1 (roaming and set as SIM for mobile data) and a Very Mobile/Wind SIM in slot #2 (not enabled for mobile data). if i remove the Very Mobile/Wind SIM card then the T-Mobile SIM works fine for mobile data, and vice versa. also the problem still occurs with Data and Battery saver modes both enabled and disabled.

the fact that an identical Teracube 2e (2020 batch) running stock Android 10 works as expected (i.e. with both SIMs installed data mobile works when selecting one SIM or the other) suggests that this is an issue with /e/ OS. and while i am currently running 1.0, this issue has existed for many months with previous versions: basically every since coming to Italy and getting the second SIM card in Feb. 2022.

any suggestions for a solution, confirmations of this bug, etc. are greatly appreciated. thanks for reading and take care!