While it does sounds like a bug, I would probably not have come across this myself.
The way I work would be to set all the patterns up for a Song using the same kit (with eight variations, pattern chains and fills). In this senario there would be no audio drop out.
I guess if I ran out of channels and wanted a different sample during a part then I might create a slightly different kit, but this would be rare as 11 channels for drums/one shots is probably enough for me as I also have the DT for samples.
I think Roland will fix this though, they should anyway.