It’s strange since most of the pills I’ve gotten over the years are perfectly flat, but occasionally they are not. I’ve posted about this years ago, but it didn’t get much traction:
Convoy S2+ Pill Issue - Shelf Not Flat
It doesn’t take much effort to correct the pills, but I assume a flatter pill is better for thermal conductivity regardless of how much thermal paste is used to fill the gap.
Hopefully all of yours will be good.