I have ITV Meridian HD in a custom mix custom bouquet in AutoBouquetsMaker although I don't think this is a problem with ABM.
When watching any channel besides ITV Meridian HD whether it's in my custom bouquet or not, when I press the power button on my remote to put the box on standby, when I turn it back on the channel is changed to ITV Meridian HD instead of still being on the channel the box was on before I put it in standby.
Also after resuming from standby when ITV Meridian HD is on I press the EPG button but it shows the EPG for the Providers > BSkyB instead of the EPG for my custom bouquet.