Alignment issues or new rear tires?
 

I got an alignment and 2 new tires for the rear. Now it seems the steering pulls slightly in either direction depending on irregularities with the road surface. The steering tracks straight on level surfaces.
Is this the alignment or the new tires causing the issue?
Also, the technician stated that he adjusted the negative camber slightly to improve inner tire wear for the rear tires. However, the alignment is in spec.

I would imagine since you have no problems on even roads but have issues on uneven roads, that your problems lies with being on uneven roads.

When I put my new tires on a while back I had a similar issue. Alignment was ok and I noticed it a lot more on roads with wear. I assumed it was due to the new tread gripping better than the old, but I'm not sure.