Sage intermittently stops inputting numbers.

Hi, one of our clients is experiencing an intermittent issue in Sage 50 Premium 2021 Desktop going back months: Once a day (time of day is not consistent) they are unable to type numbers into their program, only letters. Other programs work fine and we’ve found the most expedient workaround to be alt-tabbing into another window and back. We’ve just replaced their computer (and KB+mouse) with a brand new PC with a clean Windows 10 Pro install and the problem persists. We’ve been unable to replicate this problem ourselves and are wondering whether there is some key combo our user is accidentally hitting that silently discards numeric input. The user reports this issue is happening with the number row and the number pad, user reports this is happening on invoices and estimates. 

Sage 50 Premium 2021 Version: 28.20.0000.0001