Hi @cndopsec,
this is a known issue in the oreo build: Samsung Galaxy A3 restarts when connected to WLAN
The boot loop issue should be resolved as soon the pie build is available. Until then you could try the pie-test build that is available here: Device Roadmap : Pie , Q and Beyond - Part II - Test upgrade builds for supported devices
Direct Link to the a3xelte pie test-build: https://androidfilehost.com/?fid=8889791610682912285
Johann