Laptop overheats & shuts down when going to sleep

Essentially what happens is that when I put my laptop on sleep mode, the screen goes dark but it doesn't actually go to sleep. Instead, it will start to heat up and the fan will get increasingly louder until it shuts down a couple of minutes later. This doesn't happen every time - it ranges from once per day to once per week.

The issue first started last September and I notice that it coincided with a routine update. I've tried Googling variations of what I believe the problem to be, but just never had any luck. While it's been a nuisance, it's very minor and only makes it annoying to fall asleep with unsaved work.

Any & all advice is appreciated.
 
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