I have been using Premiere Pro CC2019 and earlier versions for years and I record a lot of live events with my Canon C100. Results have been excellent but recently (maybe since CC2018?) I have noticed that when I output the files and view them on TV the black levels seem to be pulsating and changing ever so slightly.and it is majorly distracting. It's almost like the IRE level is moving up and down on a regular cadence....seems almost to be tied to compression pattern where its updating every so many frames.

Source files are Canon C100 24fps ProRes HQ recorded via Atmos Ninja Blade.
Output is h.264 for Bluray at 40mbs via Adobe Media encoder.
I've also tried going to .mp4 with similar settings with the same results.

The material looks great on the timeline and previewing on a calibrated monitor. So....any ideas why this is happening? Also the h.264 encodings seem to have an excessive amount of macroblocking in dark areas that are distracting and I just don't recall having these issues a few years ago when I was on CC2017 and earlier.

Thanks.

Use a bluray preset. 40 is too high for most players.
turn off max render if you have a dedicated gpu and max depth.
Dont use preview files.