if you add pressure to the center of the block, can you see the temps change? it could be they just do a really bad job with estimating pressure.

if that is the case, you can "try" to fix it by taking a copper fin off an old heatsink and use it to raise up the center where the core is. or sand down any standoffs that might be holding it too high off. id have to see a picture to give a better idea.