Can't Proceed with Numeric Text Entry

Hi all! We are having an issue with a customer not being able to proceed in a software simulation after entering numeric text into a text field. Here's the scenario: 

1. specific step of the workflow is to enter a users birthday (customer can enter the birthday)
2. after entering the number 3, the slide should automatically advance to the next (this does not happen for this customer)
3. each lesson in the module is locked so the learners have to complete each one before the next. we have marked this course complete for this specific customer which should allow them to move about the course freely. it does not for them.

The trigger has both the num pad 3 and the above the keyboard 3 as options to auto advance. 

The customer is using Chrome.

There are thousands of customers who have completed this simulation without issue. However, we are stumped on why this particular user cannot proceed.Not only can they not proceed within this module once entering 3, after marking the course complete in the LMS, which unlocks all of the lessons, does not allow the customer to proceed. 

Any ideas on what could be happening? There are multiple modules that require the learner to enter dates and this customer cannot proceed on any of them. 

We would appreciate any thoughts, suggestions, feedback, whatever you got!