When I was using Safari 12 on iOS 12.4.9 (the OS version released last month) on an iPhone and an iPad mini, a search bar from https://stats.wikimedia.org/ won't display characters well while typing and/or backspacing.
At first I thought it's just the Safari 12 issue. Then I tested out Chrome 87.4280.77 (latest) and Firefox [for iOS] 29.2 (latest). Same issue persists. I even switched from default virtual keyboard to Gboard app, yet the same issue still persists.
Then I tested out the issue at Safari, Chrome, and Firefox via an iPad Pro's latest iPadOS version, 14.2. However, I have seen no issue persisting there.
Now I wonder whether it's the iOS 12 itself or browsers on iOS 12. More likely, it's either the iOS 12 itself or the devices running iOS 12 and incompatible with latest iOS/iPadOS 14.
Safari 14 via iPadOS 14.2:
Chrome via iPadOS 14.2:
Firefox via iOS 12.4.9 (iPad):
Safari 12 via iOS 12.4.9 (iPad):
Chrome via iOS 12.4.9 (iPad):
Chrome via iOS 12.4.9 (iPhone):
Safari 12 via iOS 12.4.9 (iPhone):