Torn between digging up an old thread or starting a new one. Figured it might be better to keep things all in the same place...
Anyway, I had exactly the same problem reported by the OP.
A two hour+ concert recorded onto a Kingston class 4 16gb micro SD, recorded at 96/24.
This has been automatically split by the M10 into three files, the first two of which are 2,097,148 kb and each of these files is 1 hour, 2 minutes and 8 seconds in duration. The last one is a smaller file of only a few minutes duration.
Here's the interesting part, I have two sections, one on each of the large files - towards the end (54 minutes on one, 57 minutes on the other), where I get exactly the same problem reported by the OP.
The card is a Class 4, and reputable brand.
The card was formatted (on windows) the afternoon before the concert.
At the start of the second file the glitch occurs for 10 secs before clearing and the rest of the recording, well up to the 57 minute, is spot-on perfect. This seems to be some form of hangover from the first glitch.
Strange.
Did anyone do any more testing and find an answer to this?
It does look to me like some problem in writing to the SD as each file becomes larger.