[ceph-users] Scrub stuck and 'pg has invalid (post-split) stat'

Hello, Following an upgrade from Nautilus (14.2.22) to Pacific (16.2.13), we encounter an issue with a cache pool becoming completely stuck, relevant messages below: pg xx.x has invalid (post-split) stats; must scrub before tier agent can activate In OSD logs, scrubs are starting in a loop without succeeding for all pg of this pool. What we already tried without luck so far: - shutdown / restart OSD - rebalance pg between OSD - raise the memory on OSD - repeer PG Any idea what is causing this? any help will be greatly appreciated Thanks Cédric