You should use the latest build, only use old ones if problem arises. For changes, check the LineageOS changelog for LOS16 here
What is your-- LineageOS version: LineageOS Download url: Gapps version: Did you-- wipe: restore with titanium backup: reboot after having the issue: Are you using-- a task killer: a non-stock kernel: other modifications: Provide any additional information (observations/frequency of problem/last version it worked on/etc) as needed:
Magisk worked fine for me. Gotta use 19.4 and make sure you flash OOS on both slots prior.