[davidmanze]

Extreme temperatures are reducing the lifetime/increasing the defect rate.
Customers won't be happy to have the camera failing just outside of warranty either.
Thus being cautious rather than over-confident has its merits.

 Hmm .... I've been reading around including the strip down ..... it's been established that the sensor is not the overheating problem ..... and the processor doesn't have a thermal pad as such ....   .. however, the Rams do and sort of overlap slightly onto the edge of the processor ........ other than that there's little sign of any heat sinking .....

(the Z7 for example has a thermal pad squeezed between the processor and a substantial  aluminium plate for heat dissipation attached to the rear of the camera)) ...

..... there is also much speculation about the CF express cards being a limitation though ..... as when removed the camera's so called overheating problem goes away ......... 
.. exif shows that the camera is heating up but not to any level that would be detrimental to the sort of chips found in modern day laptops ...... 
 ..... one user who dabbles in astro-photography has been doing "dark frame" measurements which are used to subtract noise from stacked images ...... he has published graphs using the exif data showing the increase in "noise levels" over time, as temperatures rise, noise rises by 24% when whichever components the exif is measuring,  reach around 61° ...... yet according to him after the camera is turned off for just a few minutes the exif showed temperatures dropped to normal running temps in spite over the continued overheating warning ...... something strange there !!

Well worth looking at this thread ....... 62° max sensor temperatures before shut down ..... but 72° temperatures after being stored in a meat safe at 0.4°C it ran for an hour ......
(shades of the Goodfellows? )

  https://www.dpreview.com/forums/thread/4511691

.... my test of the D500 in 4K video mode showed the body to get quite hot after half an hour ...... with it's lesser bit rate and the 1.5X crop would lead one to expect less heat would be generated ........
 .... yet the R5's external body temperature remains unchanged so Canons magnesium body dissipation claims make zero sense ......
 ..... whether it's thermal protection,  running time protection, or their own "professional video camera range protection" system ....... that is causing the issue will no doubt be discovered by those who have a strong interest in such matters ......

...... there's a lot of those now demanding answers!!