Only repeated headers with their other side effects seem familiar to me. I have not tried to clock those, but there are several reasons for crashes, so there would not be one right answer anyway. Those could appear when mooshimeter resumes after crashing and tries to continue logging, to minimize problems. Some early versions just crashed and if they managed to reboot after that, they would just sit there doing nothing. Much better this way, as many logging needs are not really time critical and gaps in time are fine, or at least way better option than total crash in 2 hours, to be found after a week.

Like always, first thing to try are fresh batteries. I would recommend lithiums, as alkalines will leak and ruin your toys when you least expect it.

I have been thinking about what went wrong in mooshimeters battery-level indicator and my guess is that as it only uses some direct battery voltage -> percent value conversion, lowest operational voltage must have be tested with desk power supply. In doing so, there would have been enough current for mooshimeter to operate, but with almost empty batteries at the same voltage level, it would just brownout when writing to memorycard or doing something else power intensive. If you are using alkalines, somewhere around 50% should be a warning sign and you should already replace batteries. Lithium-AA:s will work longer in any case, but i yet have no idea if it would be possible to see when they go empty with that same indicator or not.