BTW, I never understood how chainstate is stored, but it seems every run touches practically all chainstate files, based on file modification times.
Looks alright to me. During startup, Core checks the last X blocks for inconsistencies. Specifically, the debug.log prints that they've checked the last X blocks for coin database inconsistencies.
I don't think it does a full check of the entire chainstate, as it'll take too much time. Do CMIIW.