Online TB crashing Studio

I have a question about online TBs.

One of our translators is complaining that whenever she works on a job with an online TB from one of our clients, her Studio crashes. 

At the first Ctrl +  Enter she gets an "Index is out of range..." error message and then Studio crashes so quickly there's no time for a screenshot.  If she disables the TB, all is fine. 

She has the newest version of Studio. 

What can be the reason and how can we solve this? Not using the TB is not an option with the client. 

Thank you!