I tried to reproduce this but had no luck but maybe i'm not trying something that you are doing.
In the mean time, I would test to see if the values are actually changed using a microflow to eliminate the possibility that the text box without an input mask is being cached. I would just put a microflow button right next to the text box that passes the object to it. Then put a break point on the end event and check the variables tab to see if the value is set.
Did anyone find a solution to this issue? I am experiencing exactly the same thing in IE. I tried refreshing but that didn’t do anything at all. But the correct value is there if you check the variables.
Also related to the input mask, you can not delete the values in Edge, you can over write them but not delete them or backspace over them.
seems a lot like a CSS bug.
try adding something like this to your css: