@kirilkov Do you have "Show tab preview" enabled in Settings? If yes, then try disabling it and testing. If problem doesn't occur anymore, then I have a similar bug and they said it is already fixed internally.
looks like this helped. waiting for the fix! thanks
I would suggest, the Opera extension called Zoom Slider. Been using it for years. It's never failed me.
This extension just shows or set the zoom set by Opera. But this does not fix the problem itself