Internal MariaDB error code: 1927 ('Connection was killed')
I understand from the comments that your application is writing to more than one DB node. This is known for causing deadlocks, and this appears to be the underlying problem in your first crash log that you uploaded to the MariaDB Jira. If you're using a DB proxy (like MaxScale or ProxySQL), then make sure to use a read-write splitter so you write to only one node, but read from all.