Invasion of EPG by deleted channels

I have just used the Custom Firmware to mark over 130 channels as 'Hidden'. Many of these channels were not new, but ones I had previously excluded in the same way. These channels, in the ranges 400-, 500-, 600-, 700-, 800- and 900- all appeared this afternoon when I switched on. Yesterday they weren't there.

Does anyone know why these unwanted and deleted channels sometimes reappear? Perhaps I'm using the CF incorrectly.