Did you check the bead seat? (The reference line the just shows above the rim.) A tight tire can have a portion of the bead slipping down into the center channel, causing usually both an overall low and a wobble of the tire center to that side.)
I always pick up wheels with fresh tire mounts, hold by the axle and spin, looking at that line for wobbles on both sides Sometimes I have to work the tire or deflate, adjust and try again to remove the wobble. Then there are also bad tires. Best returned.