dodger46 :
Did you clean both surfaces with recommended cleaner?
Even very poorly applied but still sufficient paste should still be more than good enough to prevent CPUs from getting anywhere near their thermal limit at boot.
When I switched my 212+ from vertical flow to horizontal, I simply scraped excess paste from my previous installation, put it back in the middle, re-installed and my new temps still ended up 2-3C LOWER than before.
Only way I can imagine paste application performing this badly would be by applying paste in a closed ring pattern to seal air in the middle which would prevent paste from spreading inward to cover the main area of interest.
So my money would be on incorrect HSF installation.