My iPad automatically zooms-in whenever I switch back to a web app

Whenever I switch back to a web app installed on my iPad, it zooms-in automatically. I have to zoom-out manually all the time.

I noticed that, if I don't do any action related to zooming within the app, this automatic zoom-in behavior doesn't trigger. However, if I ever zoom-in then zoom-out (by pinching) in the page and leave it, every time I will switch back to the app (from the multitasks window, swipe with 4 fingers, click on the icon from the dock or from the home screen), it will zoom-in automatically. I have to close it and open the app back so it doesn't do this weird stuff all the time.

Is this a known bug?

I managed to reproduce it on an iPad air 2 as well as an iPad 8th Gen both running ios 14.6.