Since downloading ios12 I have discovered at least two issues
My Slingplayer app crashes at startup and my openVPN will only stay connected if I leave the openVPN app on screen, it disconnects if I hit the home button and try and open another app that I require the vpn for like my home security NVR
I have had this with several apps, and when debugging with developers it looks like it’s actually related to Screentime, if you disable screentime it may fix the problem, or reinstalling the app may resolve it.
I’d recommend you report on MacRumors -https://forums.macrumors.com/threads/macos-mojave-db-1-db-2-app-compatibility.2121547/ -no need to duplicate that resource here.
Isn’t that just choosing to log it in one of, presumably many, available public places?
Surely to “report” the issue you would be contacting a particular third party app developer or raising a radar with Apple for issues in their software?
I will give that a try, thanks
Yeah sure but that is a long-established guide for what works in a new version of an OS, oriented more towards users who want to know the status of apps.
Yes, of course you should probably raise it with the dev.
And post on MacRumors iOS 12 list 
not Mojave…
Springboard crashed whenever I tried to search from the home screen. Reported and the behavior eventually went away. Other than that, google apps sometimes crash on double click.
Tour de France app is crashing after splash page. I guess I’ll be rolling back to iOS 11 later this week.
Audm, iDTE (law firm billing software), SlingPlayer and Epson iLabel all crash on startup, so far.
CarPlay doesn’t work well with my VW at all. I’ve gone back to 11.4. Whenever parking sensors kick in it loses connection. Raised with Apple.
I am amazed how well iOS 12 works already.
I did have one crash on my iPhone X when dragging an application to a folder but apart from that, no issues so far. And man, does it feel fresh and snappy (not the looks, but the speed and animations and stuff like that)!
So far, I have not experienced an app issue. I am really impressed.
Books crashes on me when a screencast inside the book either completes or was quit. On a different book it crashes trying to open the screencast.