Could you provide the following details?
Which exact firmware version did you have before performing an update?
Did you update with Keep settings option set to on?
Could you reset one of your devices to factory default settings and check, if the issue is still present?
If reset does help, I would like you to attach a troubleshoot file to your question. Make sure the issue is present, 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.