form input not working on ios inside a popup modal

Hi folks, 

i'm finding an issue on ios mobile with input fields.  The fields work fine outside of a modal/pop, but inside and only on ios, the user can only enter a single character if any, before the field stops accepting more text.  if you keep reselecting the field, and quickly type on hte ios keypad, it'll register the character.  

as far as i can see, the field seems to remain focuses and the keypad stays visible but input stops working. 

If i take the fields out of the modal container the fields work fine / as expected.

has anyone come across this recently?

just incase anyone is experiencing this.  seems like things get pretty buggy when they're buried in multiple layers of web blocks.