Tests in BB sometimes failing with runtime error: member access within address

https://buildbot.askmonty.org/buildbot/builders/kvm-ubsan/builds/2347

binlog_encryption.rpl_parallel_stop_on_con_kill 'innodb,stmt' w4 [ fail ]  Found warnings/errors in server log file!

        Test ended at 2022-08-19 07:18:35

line

/home/buildbot/buildbot/build/mariadb-10.6.10/sql/log_event_server.cc:1731:68: runtime error: member access within address 0x7f77b8035718 which does not point to an object of type 'Format_description_log_event'

^ Found warnings in /dev/shm/var/4/log/mysqld.2.err

ok

Tests (seemingly parallel ones) that have failed with this runtime error:
binlog_encryption.rpl_parallel_incorrect_relay_pos
binlog_encryption.rpl_parallel_stop_on_con_kill
rpl.rpl_mdev8193
rpl.rpl_mdev10863
rpl.rpl_parallel2
rpl.rpl_parallel_ignore_error_on_rotate
rpl.rpl_parallel_incorrect_relay_pos
rpl.rpl_parallel_mdev6589
rpl.rpl_parallel_retry
rpl.rpl_parallel_stop_on_con_kill
rpl.rpl_parallel_temptable
rpl.rpl_relay_max_extension

The oldest occurrence in Buildbot is with bb-10.10-MDEV-28632 f852b1b153ae4d28764b314094042f23
https://buildbot.askmonty.org/buildbot/builders/kvm-ubsan/builds/2061

On my VM it seems simple enough to see the error by doing:
(10.6 af552f2903b9764e3bc0634a0037c39d1a837f4f)

./mtr rpl.rpl_mdev10863 --parallel=auto --repeat=20