[temp_account_32]

Yeah this does sound very user unfriendly, although I have to say a good validation UX is particularly difficult to code (When to validate, on submission or on losing focus to that element or instantly on input? Do you need to debounce the validation? How to present validation error messages and where? Etc.).

Your example probably stemmed from the case that the developer wanted the user to have instant feedback on validation, and instead of displaying some validation error message next to the input, they decided f-it - let's just immediately validate on input and not allow any invalid input. Bad/lazy decision, but I can see how it came to be.