I have the same problem with the Mailwasher Pro icon. I also use cCleaner.
After resetting it to 'Show icon and notifications' I ran cCleaner, there was no change to the status. It could be that I have to reboot but JOY doesn't run cCleaner often by the sounds of it and it still happens to them.
My only observation is that this is the only icon that I have that changes (when a new email appears on the server). Both icons are displayed in the customization window and both are selected 'Show icon and notifications'.
I found the solution to my problem here: Mailwasher Pro and Notification Area