Unreadable MTS videos on SD card, hex values appear shifted in the header

[abolibibelot]

Another really weird issue when I sure don't need any more...
While attempting to import MTS video files recorded with a Panasonic HDC-SD90 camcorder to my computer, I found out that about half of them were unreadable. MediaInfo doesn't recognize them, Panasonic's HD Writer fails to import them and stops the import altogether for all the remaining files.
Looking at those files in WinHex, I noticed that some bits in the header appear shifted by exactly “88” :

Here file 00037.MTS is correct and readable, whereas 00038.MTS is unreadable, and you can see that everything except the “FF” is shifted by “88” in hexadecimal. All the unreadable files have the same pattern.
WTF is going on here ? Is it a known issue ? Or is it somehow normal on those cameras, could it mean for instance that those files are not finalized or something like that ? How can this be fixed with no fuss ?

[abolibibelot]

Well, at least that one solved itself : I retried a few hours later, without touching anything in the mean time, I didn't even remove the SD card, or reboot, now all the files are fine... O_O Kinda spooky... Has anyone ever seen anything like this ? Is my computer possessed by evil forces ? I was doing video processing when the import started (reviewing an Avisynth script with many interpolations of bad frames in AVSPMod and VirtualDub2, with an automation tool called Sawbones), could it somehow explain that weirdness ?