As far as I know a Pattern can be grayscale, Lab, RGB or CMYK, but not multichannel.
I may not quite understand what you are ralking about – but what do you want to achieve with those additiopnal channels anyway?
In any case you seem to have one channel visible but another one selected – could that be part of your issue?
Actually I found out after long time struggling. when I post here I suddenly get it to work. I probably get confused by layer and channel. I'm talking about RGB and multichannel, but I found out, thanks anyway.