The firmware might resolve the issue, we only work with Network IP products so have no experience of the issue you describe on any analog DVR.
You are currently running a 2015 firmware and there were a few versions between that and the latest version that I've linked you to above, so I would expect there to be quite a few patches/fixes within that firmware (although I should point out that that latest firmware is from 2018 & this DVR appears to have been end of life for many years so it could just be a hardware failure after many years of use).