users cannot comment on cards on one board only

Question

Hello, On our account, we have an admin and a few users. The users are suddenly not able to write a new comment on cards.  They can edit previous comments, but cannot comment themselves. It's only for ONE board, which is also odd. The comment box does not appear to add a comment for them. In my coworker's view, there is NO "Write a comment" box that appears above the other comments, so she can edit previous comments, but she cannot make a new comment. Please advise. 
Thank you.

Gaurav Kataria · Accepted Answer

We had a software bug today that is causing some members to not be able to post comments on a card. We are working on fixing it.