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 |
|
+---------------------------+--------+
|
Major 