VMNames limit reached. Cannot create npvdi10

First of all, we're NOT using composer...

I have a small pool of test desktops with a naming pattern of npvdi{n:fixed=1}

Under Pool Settings I have "Delete Desktop after logoff" set to Yes.

So I log in and out a few times and it eventually deletes and builds everything up to npvid09, and then says "VMNames limit reached. Cannot create npvdi10"

I sort of expected the View manager to restart at npvid00 once it reached the end of the names it could use.

Does anyone have any ideas or input about this?