Note: I reported this in a comment on MDEV-26391, but as instructed, I'm opening a bug.

I tried out the new wsrep_mode = BF_ABORT_MARIABACKUP setting and found that, when using wsrep_sst_method = mariabackup, a node never returns from Donor/Desynced to Synced after a serving as an SST donor.

I've attached a tarball containing a docker-compose environment that reliably reproduces the issue. The logs directory contains the logs from each node and queries that show the 'wsrep_%' status and PROCESSLIST.

After the cluster is formed, 2 of the 3 nodes have

+---------------------------+----------------+

| Variable_name             | Value          |

+---------------------------+----------------+

| wsrep_local_state_comment | Donor/Desynced |

+---------------------------+----------------+

while the last node to join the cluster has

+---------------------------+--------+

| Variable_name             | Value  |

+---------------------------+--------+

| wsrep_local_state_comment | Synced |

+---------------------------+--------+