A couple of weeks ago we have upgraded our MariaDB + Galera (3 nodes) cluster to the last stable version - 10.5.4. In our configuration, all writes go to 1 node only. And we started facing deadlocks (gap locking) issue on that node. Nothing was changed from the DB side except upgrade and nothing was changed from the application side.
Could you please advise on this and please let me know what additional information will you require for further investigation?