Something Strange?

Noticed something strange yesterday and need the usual voices of experience...

I have a Collette climbing rose about 3 years old, 6 feet tall. Half of the bush is blooming as usual. Other half is blooming with single red roses that look like small versions of the Knockout rose planted nearby?

Is this even possible?

Check for the graft on the rose and see if the branch with red flowers came out below the join. The red flowers are probably coming from the root stock.

Ardesia- Thanks, I'll check it out this evening. That would make sense!
Should I prune it off?

I think I would, it might be draining some of the energy that should go to Collette.

Ardesia- Collette sends her thanks. Don't know how I'd grow a weed
without y'all.