Increased body testicular temperature can increase the risk of Sertoli cell cancer but the risk would be minimal because you don't keep "them" that warm all the time.
If you cut off blood supply by tucking (again rare) you can cause the testes to die and worse would be when blood flow return you could release cytokines that could cause strokes or death (not likely)
You asked if there is a risk, the answer would be yes but minimal
