Thank you very much, so this is actually something to do with that specific IOS version. I assume there must be a some sort of a difference between the version I am testing on, even though it says 15.1, maybe something to do with the locale.
Sorry to bother you with this, but can you please try these two input fields on this test page: https://wp-dreams.com/test/test.html
Does the issue appear on any of them?