That would be game mechanics and the Shiekah Slate's temp reading DOES give 'error' report in the game which I think is Nintendo proving a point that it can glitch out but don't want to leave the player stranded as they were still reeling in from the Skwyard Sword hand holding mechanics. If...
Those shrines may be purposely hardened just for that area because IT IS A STUPID VOLCANO!!!
It's like the power grid in Las Vegas is designed better then the grid in Portland. Central Hyrule is NOT a volcano nor ever considered to be that way. If you read my post fully you'd see where I'm...
Back Story: Here in Oregon we are going for the all time record for PDX which was 107F in the multi day 100F heat wave in August 1981. Here is the data if you care to look: National Weather Service - NWS Portland Here is a sample of that time period...