Ios keyboard problem

I am trying to open my website with wkwebview. I have a comment bar and when I click the bar, keyboard opens. After that, when I close keyboard, there is white space on the page.

I tried to use IQKeyboardManager to fix it but interesting thing is it works fine in iOS 13.2 and above versions. But for example on iphone6 the problem continue.

How can I fix that? Any suggestion? Thanks

It could be the keyboard problem or the iOS system issue. If it is the former, you may have to seek official support. If it is the latter, then you could fic it by yourself. That is using any professional iOS system repair tools, which can resolve keyboard not working on ios devices without data loss.