Hmm, I think the problem is still there, but you may have masked it, or found a workaround.
None of my channels have any tuner assigned. When no tuner is assigned, MC just uses the next available. It picks for itself, instead of using an "Assigned" tuner. That way when you are doing multiple recordings, or recording and watching live TV, MC can just switch to any tuner available.
So, either one of your tuners is having trouble and by assigning a tuner to channels you are avoiding using the bad tuner, or this version of MC is having trouble selecting a tuner with your specific hardware. Or maybe MC is having trouble getting the EPG data using one of your tuners. You didn't say which EPG source you use, but if it is the EPG data broadcast OTA on ASTC channels, that could explain why you only got two channels of EPG data.
I suspect that you will see more problems in future, and they may be hard to work out what is going on. Check your recording continue to work properly.