hiding from print-out user-defined props doesn't take effect until OL restarts

Greets,

I'm using RDOUserPropery.Printable property to make it so our user-def props
don't print. (Sorry if that was redundant.) It works, but not until I have
restarted Outlook. I check the item's Modified property before changing
anything and log a warning if calling save doesn't set it to False. I do
the same thing again after changing it

Does this mean I'm leaking a reference somewhere? Hmm I see that if I
unload my AddIn the properties are hidden, that would seem to pretty-well...

hiding from print-out user-defined props doesn't take effect until OL restarts