Once i had similar problem, and I tried to change different settings, but i don't remember, which helped.
I have several cameras, and one of them worked good, but other inspite of proper settings, recorded all day long instead of recording on moving. I've copied the settings of the nomal working camera to improper camera and it became ok,
Also there is a quota settings in the NVR for each cam,- maybe reseting it or reducing it for every cam will help.
I always set quota to less amount. For example: a have 1000 GB disk and 1st cam has 400 Gb and 2nd cam has 400 Gb, so the disk is never full. I don't know why i do so, but maybe it helps to avoid problems (maybe there are some service data need to have free space).
Also after all changes i think you should clear the disk and check during some time.