Sorry it may take a while.
That said, one thing more came to my mind about the correlation: the affected hosts were all installed between May 2020 and March 2021, while the unaffected host was installed in October 2021. (The kernel versions correlate in inverse by coincidence). That means it may be worth to testing going from whatever LXD version (and potentially other packages) it was back when 20.04 was released or March 2021.
I also observed that 5.3 had caused minor data corruption. When migrating one of the hosts back to 5.2, one of its containers would no longer start up due to Lxc snapshot and lxc start Error: Instance snapshot record count doesn't match instance snapshot volume record count. The container had obviously started nicely on 5.2 before so the inconsistency was introduced during its brief encounter with 5.3.