I'm the same.Not sure if this helps or hinders but I have Cardinal set for BBC 2 HD tonight (2 episodes and set as a series). Next weeks Cardinal has not been set to record (both on the box and in WebIf/RS). I have checked the Series CRIDs and they are the same (fp.bbc.co.uk/p/3Z4HLU).
The Humax may not add next weeks episodes until after this weeks episodes have aired. I am not sure of all the times the humax checks for new episodes.
Schedchk only checks the next 36 hours (Threshold value) for missing episodes so wont be looking that far ahead.