KMail--Can't Delete Phantom Message(s)

[Null <nullpointer@root-user.org>]

Using KMail 3.5.9 from unstable.

I sometimes get phantom messages, which usually have their subject 
line in strikethru. These messages can't be read, moved to the 
trash, or deleted.  Generally they are in my spam folder, but not 
always. They only way I have found to get rid of them is to delete 
the folder entirely, then recreate it, or to delete the folder 
indexes.

Is anyone else having this problem? Any suggestions?

Thanks.