Completely bonkers KMail yet again

Hello list,

It's really going mad today. I've grown used to having to run akonadiconsole 
to delete a folder's akonadi cache, about once daily. This morning, however, 
when I fired up KMail, it had no folders and no messages. After yet another 
reboot, they all appeared again.

After pulling down new mail, THREE folders had duplicate messages, and 
nowadays KMail doesn't just delete one of them when I tell it to, it whinges 
about multiple instances and refuses to do anything.

When are we going to see some progress with fixing this bag of rusty nails? 
Who writes unmaintainable code anyway?

-- 
Regards,
Peter.

Gentoo kernel 4.12.12
dev-qt/qtcore-4.8.7-r2
kde-plasma/plasma-meta-5.10.5
kde-frameworks/plasma-5.37.0
kde-apps/kdepim-meta-17.04.3
kde-apps/kmail-17.04.3