From what I understand, it's up to Google when this gets fixed. Nothing new on my end.
Did you try this?
No seeing as Asus have said it's a known bug that needs Google to resolve.
As I wrote here, Smart Lock works perfectly for me. It doesn't work for you, and you'll wait for Google to fix it so that it always works for everyone in various conditions. However, when it will do is a question, because Google did not correct some of its issues even after 10 years ...
At the same time, clearing caches does not cost you anything at all, you will not lose anything, you will do it yourself and you do not have to wait for anyone. Then restart for sure and see if it helped. It won't take more than 2 minutes, I think it's worth a try.
I tried that as you recommended and hasn't made much difference. The phone still locks itself when I wouldn't expect it to especially in the current climate when I'm mostly working from home. Guess will have to wait to see if Google fixes it or Android 11 arrives, whichever is sooner.
So at least you tried. By the way, it could eliminate problems you didn't even know about yet :)
You could still try to configure Smart Lock again from the scratch as it helped some users.
I just hope you realize how Smart Lock actually works. When you turn on the phone with the side power key at Home, you will not immediately see the home screen, but the lock screen, which is unlocked in advance (the unlocked lock is displayed at the top and it is written at the bottom that Unlocking is maintained by the TrustAgent function). You still need to swipe from bottom to top for the home screen to appear, but you don't need to use your fingerprint.
It intermittently doesn't work right for me either when keeping unlocked by location. If I'm home all day I'll have to login 2 or 3 times at least. It ALWAYS works for me when tying it to a Bluetooth device. My assumption is that the GPS signal breaks occasionally and causes it to lock. It did it on my previous phone too. It still stupifies me that it doesn't give the option to keep unlocked when connected to a trusted wifi/router.