I have been plagued by this bug for a very long time. Today I found out, that for ages there has been an error message in my mysql/mariadb log-file:
[ERROR] Incorrect definition of table mysql.event: expected column 'sql_mode' at position 14 to have type set ...
This is the first time I saw this error, as there is no other application than akonadi using mariadb on my pc and akonadi was never complaining. This mariadb-error could be fixed by running mysql_upgrade (google it to find an explanation, this is due to an incomplete upgrade of the mariadb-package)
After fixing the database, kmail has not been showing duplicated mails any longer. Also filters have been working flawlessly.
Version KMail 5.13.3 (19.12.3)
OS Gentoo Linux
I have been plagued by this bug for a very long time. Today I found out, that for ages there has been an error message in my mysql/mariadb log-file:
[ERROR] Incorrect definition of table mysql.event: expected column 'sql_mode' at position 14 to have type set ...
This is the first time I saw this error, as there is no other application than akonadi using mariadb on my pc and akonadi was never complaining. This mariadb-error could be fixed by running mysql_upgrade (google it to find an explanation, this is due to an incomplete upgrade of the mariadb-package)
After fixing the database, kmail has not been showing duplicated mails any longer. Also filters have been working flawlessly.