Confused about merge...

So, I have two streams; StreamA and StreamB.

I am wanting to deliver all changes delivered to StreamA to StreamB, so what I did was the following:

1) Created repo workspace from StreamB
2) Changed Flow Target to StreamA
3) Accepted all incoming baselines and changesets (required a little merging on a couple of files)
4) Changed flow target back to StreamB

I see all my outgoing changesets and baselines as I would expect.

BUT I am also seeing a bunch of INCOMING baselines. Why?