Hi all!

I purchased this vehicle used in Sept 2020, initially it had a bad passenger side wheel bearing.  I had my mechanic install new front brakes/rotors/hub assemblies on both sides.  The tires were installed/balanced via Treadquarters.  The brakes and rotors were OEM parts.  The hub assemblies, I admit, I went just a  little cheaper on.  Tires were Otani kc2000 and Achilles sport.  On the highway, at speeds 50-70 mph there is a "hum" I can hear in the cabin.  This hum is present at the speeds mentioned whether I'm using the accelerator to maintain speed or if the car is coasting down hill, etc.  I've been driving like this for a little over a month or so.

I took it to the dealer to see if they can hear/figure out what the noise is.  The dealers inspection revealed I had mismatched tire size vs rim size.  My vehicle has staggered tires.  Apparently Treadquarters installed the larger tire on the smaller rim and installed in the front driver.  Passenger side tire had the larger rim with smaller tire..  Vice versa with the rear.  Yeah it was all mixed up and wonky.  After the dealer matched up everything correctly, they test drove and heard the same sound I was talking about and said it was a bad  hub assembly as the result of mismatched tires.  I will say after they returned the car to me, aside from the "hub assembly noise", the car ran/felt noticeably better with proper tire/rim sizes where they needed to be.  

Any one have experience with hub assemblies going bad that fast? or possibly defective assemblies to begin with?  I'm in a little disbelief here but lack the skill to properly diagnose