cupping rear tire...... alignment or suspension?

i have a 10 wheeler 90k alignment done 3 weeks ago for new steers
noticed a couple days ago front inner rear axle tire, inner tread near frame is scalloping
my torsion bar bushing look decent but showing a little cracking
i when i was driving other day i heard a loud bang from the back as if i hit i big rock but there was no rock.
few hours later, drove off curb on that side at 5mph while making a tight right turn. didnt hit curb, just rolled on pedestrian walkway and off shallow curb
truck has a little body roll, is it possible it needs to be realigned again or is the scalloping in that manner caused by something broke or bent in the suspension.
scalloping only on the one tire

 

Could the tire be out if balance, even if being ok for 90k? I have been getting a slight vibration when steering into long sharp right curves on the highway. Wheel does not shake.. Does not happen on every right curve and never on left