It seems the deadtime checking was broken by commit 70fa7e81.
It seems that since 70fa7e81 check_open_pipes() which checks the number of existing policy handles doesn't go back to 0 after smbd's startup code has intialized the RPC services which create policy handles as part of the initialisation. That code in part doesn't close the handles explicitly and instead relies on closing the pipe to free the associated policy handles.
Since 70fa7e81 the s3 code lacks the logic to decerement the numner of open policy handles when an pipe or association group is closed.