A-HA! That was the culprit.
(Re-)moving ~/var/check_mk/precompiled_checks resolved all the warnings / backtraces and cmk -vvR --debug went through.
Thanks for your suggestion to compare to a clean site!
A-HA! That was the culprit.
(Re-)moving ~/var/check_mk/precompiled_checks resolved all the warnings / backtraces and cmk -vvR --debug went through.
Thanks for your suggestion to compare to a clean site!