This seems to be be cured by either restarting the service or "refreshing" camera settings by opening the camera settings and just pressing ok. This makes me suspect the service is somehow forgetting camera settings and using some kind of defaults.
Also, I have a setup which has 7x Hikvision/Dahua cameras of 2-4MP and 3 (remote, over internet) 640x480 Logitech cameras (don't ask
and about 12 hours after a service restart or camera refresh the issue starts reoccurring, one by one, until none of the HD cameras are recording. It does NOT, however, affect the remote 640x480 cameras for some weird reason, they continue recording just fine. It also would not seem to be related to the amount of alerts or anything like that as some of the HD cameras get way less (or even no) alerts and the remote cams get loads. The 00 second recordings also occur if triggering the alert manually.This is something related to version 5, never had this problem in version 4. I also believe it started occurring after either the last update or the one before that, the first time I noticed it was Tuesday this week but it could have been earlier without me noticing.