Diagnosing intermittent flicker (Series X, not VRR issue)

Hello, I'm posting in hopes of diagnosing the cause of an issue I've been having while gaming. Hopefully this doesn't come across as long winded, I'm just trying to be as thorough as possible in order to get relevant input.

To preface, I've had the console since day one, and never had any issues on my older samsung TV (4k 60hz panel with no major gaming features). I upgraded to a new TV a few days ago (hisense u8k, 120hz, freesync etc.), and I noticed a strange visual occurrence while playing starfield that could be described as a flicker. It is totally intermittent, typically occurring a single time every five minutes or so. It isn't a flashing or strobing, such as what is typically associated with vrr; the screen doesn't go black, nothing else wrong with the image. Just one instance of the flicker as though you're blinking.

Here's the kicker. I disabled vrr on the xbox, and freesync on my television. Tested different games to make sure it wasn't an issue with starfield directly. The problem persisted. Checked the hdmi cable, all good, problem persisted. As a hail mary I changed the refresh rate in the xbox settings from 120hz to 60hz, and the visual anomaly I'd been seeing didn't happen a single time in an hour of gaming.

So I've seemingly resolved the issue, at least for now. But have no idea why it was happening with those settings enabled. I want to establish whether or not there is something wrong with the new TV, or if this is some known issue that occurs when the higher refresh rate is enabled. Whether it be on certain TV's, software gremlins, etc. If you've read this far, thank you for your time. I would greatly appreciate any input or answers!

:)