Hyperdeck Mini missing end of recording, creates mcc

I record the same meeting, in the same manner, three times a month. It's usually 5 or 6 hours and has several stops and starts. Now the third time in the past dozen meetings the last file created is missing the last couple of minutes. It's always the last recording of the day (we stop recording at the breaks). Each time this happens it also creates an empty .mcc file. What could be going on?

Obviously, the client does not find this acceptable. Last week I bought another Hyperdeck. The same thing happened.

We've had it happen occasionally on our system as well but it's now happening with almost every recording, essentially making the hyperdeck useless.

Do you get the following message when adding it to a Windows PC? I've tested it with two Sandisk Extreme cards and both are exhibiting this issue now.