kmail: strange problem

[Timothy Murphy]

I've noticed a strange problem with kmail over the last 2 months or so.
If I delete an email (with "d" or clicking on "Move to Trash")
it does not disappear.
Exiting from kmail and re-starting it does not solve the problem,
but logging out and in again does.

I'm running kmail with dovecot/postfix
(collecting email on my Fedora-23/KDE laptop from my home server).

I wonder if anyone else has seen this?
It doesn't always occur - about once a day, or one time in four.