If the temps are over 70C it is possible they have, over time, caused problems/damage. Turning off like that and needing time to turn back on seems more like temp than anything else.
If it is under warranty, I would contact the manufacturer. If not, I would monitor the temps for all aspects/components and see how high they get to when it cuts out. You really don't want to keep running it if the temps are causing the problem as, soon enough, it would fry something and then the device won't run at all until that is fixed. Also some GPUs and CPUs are very sensitive. So even temps lower than most would consider 'high' can cause them to react.