Just tried that now 
same error happens. Could not find anything related on a quick search on the kodi.tv forums. Maybe it’s really just me that is affected. We can leave it as I can run with a new created db and resync watched status with trakt (as soon as I’m able to install it )
Update: found something with same symptoms: shared library (mariadb) problem after migrating to matrix but running mysql_upgrade did not help, same error comes up.
Update2: definitely a database problem. In case someone stumbles on the same problem and mysql_upgrade alone does not fix it, this is what I did to get it working again using a new mariadb docker (warning, I’m a noob):
on old mariadb (console inside docker):
mysqldump --all-databases > /config/sql_file.sql
copy file to a new mariadb installation
on new mariadb (console inside docker):
mysql -u root -p < /config/sql_file.sql
don’t know if these steps are also nessesairy:
mysql_upgrade -u root -p
mysql -u root -p
GRANT ALL ON *.* TO 'kodi';
flush privileges;