@entropicsoul I am in the same boat and also did what ultraj said and went back down to the 77 branch which removed a lot of the memory usage issues i was coming up again. I was hoping the 80 branch would fix it but looks like its still exists.
Let's count. Chromium and Opera has 4-week release cycle now. Opera 81 Developer will be in beta very soon, possibly next week. Plus 4 weeks per cycle.
Perhaps Opera 81 will become Stable in 5 weeks, maybe a little longer.
But the developers can fix the bug for the 80th version earlier.
For now you can check if this bug is fixed in the Developer version yourself using Opera developer (Portable version).
Better check, because this bug was reproduced for me only after changing the theme in Win 7, but it did not appear if this was not done. Perhaps these are 2 different bugs with similar symptoms.
I have no longer a bug with the address bar in Opera 81 Developer. Win 7x64.