2013 Ford Edge Transfer Case & Rear Differential Damage

My 2013 Ford Edge had a different brand of
tires put on rear of car. A few weeks later the
transfer case broke and locked up the front
end. Had to be towed. Was repaired by tire
shop who admitted a mistake with putting 2
different sets of tires on the car. A few weeks
after the replacement of the transfer case it
broke again. Transmission shop said part
must have been faulty. Replaced the transfer
case again. The day after picking up following
the repair it broke down again. This time the
transmission shop says the transfer case is ok
but the rear diff is damaged. He said he
doesn’t think it’s related but timing is strange.
Could the two issues be related? It’s an
expensive fix and I didn’t have the issue until
after the tire issue. He doesn’t want to say it’s
related and deal with the claims guy again.