Ok, I fixed it!
I sanded .006 off the base, cleaned everything up, used brasso on the inside of the IHS to get it real clean again, reapplied conductonaut and put 8 drops of high temp silicone around the heat spreader and made sure not to use too much force in the relid tool. Let it sit overnight, popped it in just now and didn't fully tighten the EK WB and 5.0GHz 1.3V 1344 Prime temps are 50°C average with all cores within a couple degrees of each other.
I've attached pics. You can see on the die I was a little worried about those scratches/scuffs, and the inside of the IHS was all black which I thought might have been hurting things. And looking at the substrate on end you can see it's warped. some further reading shows that others have the same issues when they use these long term without glueing the IHS back on. Then force from modern WB and HS&Fs puts too much pressure on the substrate if its not glued. That explains why I had issues glueing this one as well, the heatspreader wasn't sitting right against the substrate.
So lesson learned, glue these things after delidding. My other two I glued right away are fine. hopefully this one stays fine now too.
Last edited by Bun-Bun; 06-19-2019 at 08:49 AM.