I have an issue with ng-pattern. It works perfectly when adding characters to the input, it vaildates and shows error when invalid but acts weirdly while deleting characters from the input even if its is a valid string. If you delete a character from the input it show invalid and if you delete one more character it shows it as a valid. this repeats for every character you delete.

I observed this issue in 1.2.18, 1.3.15 and 1.4.0.rc2
I have added an example in the plunker.

http://plnkr.co/edit/A4kHHthnEYzaxyVzu7w9?p=preview