I have the solution for you all.
I was using a usb3 extension cable and the sandisk 32GB was getting very hot.
(I previously had a sandisk OTG in there, and it too got frighteninly hot)
That cable had plastic shrouding over all of the female socket.
I looked through my previous ebay purchases, and found a 1M usb 3 cable with the female end bare metal (no plastic covering).
I tested the 32GB in it for 30 minutes, and just ejected it now, and it is slightly warm (NOT HOT)
I did not have any fan, and the room is 20C.
Another thing to be wary of, is ensuring you get a cable with a snug fit. For two reasons -
The cable I previously purchased was most likely the same as this current ebay listing -
1M USB 3.0 Extension Data Cable SuperSpeed - A Male to A Female - AU STOCK
It was many months ago when I purchased mine.
I just rang the company, and they tell me that they have not changed supplier for 8 months, so there is a good chance that the current ebay listing (above link), is identical to mine.
PS I have just ordered some more, so I will report back to confirm whether they are the same. (should only takes days, as they and I, are both in Melbourne Vic Australia)