I know it’s annoying when other people reply “doesn’t happen for me”, but that’s true. DEVONthink Pro Office works fine on Mojave over here.
If you’ve already tried the obvious (reboot; empty the DEVONthink cache; force DEVONthink to create a new preference file) then perhaps the best course of action is to open a ticket with Support, otherwise the rest of us who have no experience with your particular computer can only reply “duh, I dunno”.
The error no longer occurs if Accessibility > Display > Reduce Transparency is DISABLED AND Accessibility > Mouse & Trackpad > Trackpad Options > Enable Motion is ENABLED (option does not matter).
… I have also been able to reconstruct this on a different Macbook … note that DEVONthink must be restarted after changing the settings !!!
Nevertheless, many thanks for your commitment and your help!