Track is receiving unwanted send from a bus

I tried searching for this issue, but I'm not sure what terms would yield what I'm looking for. Anyway...
I'm using X2 Studio. I've got this track (bass) that's outed to the master bus. I've also got a bus (drum parallel compression) that is also routed to the master bus. These are among several other tracks and buses. For some reason, the drum PC bus is also routing to the bass track but I can't figure out why it is doing this. As far as I can tell, there are no routing options set to send or receive this relationship. The bass clip itself is clean and sounds fine when the drum PC bus is muted.
 
I can't imagine this is a bug, so I must be overlooking something. Would anyone care to help walk me through what could be going on?
 
EDIT: This may actually be quite a different issue. Before, the bass track was the only track routed straight to the master bus. When testing the problem described above, I soloed the bass track (and heard compressed drums as well). Well, muting the bass track still plays the compressed drums. They aren't alone either. I have an auxiliary reverb bus that also ignores the solo command. This is, at least, a much less significant issue than what I thought I had.