Same problem here, random on different cameras. PTZ disabled, fixed cameras. Some are wireless, some are wired. Wireless are 1280x720, wired are 1920x1080.
I don't care the border turning yellow per se but, when the border is yellow, it's not only to be pretty, it indicates motion detection doesn't work and I did confirm it's not triggering if motion happens when the border is yellow. In my case, it meant some cameras weren't triggering more than 50% of the time.
I recreated a camera from scratch, same camera but new definition, new IP and all, and the problem didn't come back for that camera so, it's not a camera problem.
I'm running an Intel I7 with 16G of RAM and a Seagate Purple 2TB drive for video files, so, plenty of power. The Win10Pro OS is on a separate drive.
I disabled some cameras and now only have 5 active, to see if the problem would still be there and it made no difference.
I changed to Gaussian and is seems to be OK for now but it shouldn't act that way.
If your answer consist of of telling me to "read the manual", spitting-out the manual's content, telling me to disable the border or stuff like this, please refrain from answering. Sorry to be blunt but, by reading the forum, I noticed some people like to reply only for the pleasure of raising their post count and read themselves back, but don't really read the question asked or take time to articulate a useful reply. Or maybe they simply like to belittle those who don't know as much as they do (or think they do...)?
Thanks all and have a great day?