Flickering and poor quality output from CC2019 and CC2018

OK. This is going to be a little long so bear with me as I try to get all the facts out there so there is a clear picture of what is going on.

I am a professional video editor and shoot and have been using Adobe Products for 20 years. I edit on a high end Windows 10 workstation and do not use any Macs.One of my responsibilities is to film live stage performances at our local university for archival and theater use. I have a Canon C100 and Canon XL-H1 that I still use as it has great zoom range for closeups on live performances. I record footage from both camera to external Atmos recorders in ProRes HQ for the actual editing source material.

I take this footage and import it into Premiere Pro, Color Correct and do some A/B creative editing between wides and closups. I render to H.264 .mp4 for local storage as well as h.264 for Bluray, and mpeg2 for DVD versions. It has always worked perfect and the resulting footage was very clean and impressive to see. I have done this in various versions of CC through the years and the issue I am about to describe just started.

I started this latest project 1 month ago on CC2019. I imported all of the ProRes footage and laid out a 1920x1080 timeline. I proceeded to do a edit a 2 hour project to it's completion. The project in question is admittedly a little darker than usual as this stage play used lower key lighting. But previewing it while I edit on a calibrated HD monitor looks really good.

Now when I export to h.264 at 25mbps (always use this and it looks great) I am experiencing very bad encoding issues. The first think you notice upon viewing is that before the lights come up the dark auditorium is extra noisy and there is a pulsating or flickering quality to the video....as if the black levels are jumping up and down rapidly. My wife says it looks like lightning flashes (though not that bright). During dissolves it breaks up worse than normal. When we cut to the closeups and the lighting comes up the actors and the stage that is lit looks decent but everywhere that is even remotely dark is still riddled with blocks and flickering. It really looks unacceptable. In comparison, my previous projects I checked show no blocking in the darker areas....or at least it is so minimal as to not be noticeable at a normal viewing angle. Also no flickering either.

Now having a background in IT, I am excellent troubleshooter so I have tried a number of things with no good answers. I have moved the project to a completely different computer and rendered with the same results. I have outputted to ProRes HQ with the same issues. I have output to DNX with same issues. I do not know what is causing this. I even created a new empty project, brought in a single clip and exported and the problem still exists so it is likely not a corrupt project. The interesting thing is I took that same single clip and imported into Premiere CC 2015 and exported it and it looks beautiful. Amazing. Now I am more confused.

As a last ditch effort to get this project output so I can actually deliver it (keep in mind the actual project looks great on the timeline still) I modifed the prproj file using am xml editor so that I could open it in Premiere CC 2018 and hopefully output it successfully. While I am able to open the project and actually edit, the results of the output file are the same. Flickering and poor compression.  I proceeded to modify the .prproj file again and was able to open it in CC 2015 albeit there are a ton of issues as audio filters and lumetri are massively different so I would have to do major work to get it back to a fully edited state. I did however export a small segment and it seems to look really good from there. So CC2015 is outputting properly.

So.....I've spent the better part of 48 hours trying to get my 2 hour complex edit out of Adobe Premiere without the export process screwing up the quality so bad that clients will complain. I know that h.264 will not look as good as ProRes but honestly it still looks darn good at higher bitrates. Anyone have any ideas? It seems like something about the export from CC 2019 (and maybe 2018) mucks up the video and it's putting me in hot water with the university as they want this latest project delivered this week.

Help!!!!!