I start kmail once a day. About once a month, the filtering is not done. "Selecting all the messages" and "Applying all the filters" once more: no filtering. It needs to use the command "akonadictl restart" to get it filtered. What to look after to get a log-file with any hints? Reproducible: Sometimes
It is NOT a filter bug. It is a synchronisation bug. A fix is coming soon.
The bug is fixed. It was a kdepimlibs/akonadi problem. Details can be seen at: https://git.reviewboard.kde.org/r/112062/
Could bug 323455 be a duplicate of this one?