I am having a similar problem - Amiko Alien2. Both of them are tuned to 28.2 and I have a UK S*y subscription. I am using EMUs OSCAM_YMOD or OSCAM7884, both do the same. I can record one channel that uses the EMU and watch another that also requires the EMU then I get a blank screen. logging is showing me a request is made to my S*y card for both channels and returned.
The HDMU Softcam Control is only showing one cam Oscam_ymod - I have the plugin Alternative Softcam Manager, which I use instead, because it shows the other cams.
Any ideas?