HTML5 input type & " issue when partial information entered

I accidently submitted the post before finishing the subject line:
HTML5 input type & "mask" issue when partial information entered
I have a text field with the HTML5 input type "Tel number" and the Mask: "(999) 999-9999".
If I enter a number let's say "800" and then I lose focus of the text field by clicking another window, the number also disappears. Is there any way to keep the text stationary while I switch to another window? I notice this with other mask settings I select.
The second issue I'm having is copy and paste. If I copy a number that is let's say "8001234567" and then paste it in the box, how do I get it to display as "(800) 123-4567"? Instead, I first have to highlight the whole text field and then paste. When I paste, it will only fill out "(800) 123-456_"
I'm running v9.6 67464, and able to replicate this on firefox, chrome, android phone, and android tablet