consider adding post-submit test that runs PME with 2xNN kernels
A recent fix for the 2xNN PME kernels highlighted that whenever some nonbonded kernel flavor is not favorable on any of the supported SIMD platforms, it can easily break as it goes untested in either of the testing tiers.
To address the issue on the short-/mid-term we could trigger 2xNN kernels in one of the builds in e.g. the post-submit matrix (requires an env var per comment by Berk on the change).
(Note that a better long-term solution would of course be unit test for each and every supported kernel flavor and cluster width.)