This is now happening for me using newest Opera beta as well.
It begs the rather unnerving question; are projects older than Chromium version 85 confirmed to work on version 85 (and beyond) at all? Then again, I guess there would be more threads about it on here, huh.
Even if this issue is only on my end - to me it's disconcertingly beginning to reinforce the fact that using a browser to run the game engine is just another way something may or may not break with any given update.
What kind of additional information do you need? I have this issue on newest Opera beta, newest stable release of Chrome, newest Construct 3, newest Windows 10 update.