The issue might have occurred due to updating with Keep settings. There is a huge gap of various developments, reworks, updates and new features in between.
I would suggest to reset your devices to factory defaults. If issues persist, attach a troubleshoot file to your question. Please, replicate the issue, then access router's WebUI, go to System -> Administration -> Troubleshoot section and download troubleshoot file from there. The logs in the file might provide more insight into the issue.
Attached files are private and visible only to Teltonika Moderators.