Cutscenes causing PC to suddenly Shut Down

So I'm having this incredibly irritating issue of my PC just abruptly shutting down in the midst of extended cutscenes. I'm not sure at all why it's happening as it has not once occurred during gameplay, or any other non-FFXIV task for that matter. I've even gone as far as to revert hardware overclocks to account for any instability, but I highly doubt the game's cutscenes are pushing my PC to its limits and thermals are nowhere near any level of concern. I've run 3DMark Firestrike benchmarks repeatedly before, as well as gone through hours of continuous gameplay in games such as Metro: Exodus, Monster Hunter: World, and Nioh 2, which all easily require exponentially more hardware power.

Relevant Hardware
CPU: AMD Ryzen 9 3900X
RAM: Corsair Vengeance 64GB DDR4
GPU: EVGA RTX 2080 Ti FTW3
PSU: Corsair HX1000i 80+ Platinum

Sometimes after my PC shuts down and I restart the game, the cutscene may play through without issue. But recently, I just finished the Amaurot dungeon and the following cutscene refuses to play through without shutting down my PC, so I had to skip it entirely. And then, the cutscene after the trial fight following Amaurot does the same.

Hopefully someone can shed some light as to why this issue persists the way it does.

Update: I was finally able to play the Amaurot ending cutscene from 'The Unending Journey' after dropping my FPS cap down to 60FPS. Although, I'm not sure if I was able to play it because of the FPS cap drop or if the intensity of the scene differs from whether it's played through 'The Unending Journey' or not. Regardless, I find it strange that lowering my FPS cap would make a difference as it still had a prior cap, which was at 120FPS, and it had no problem sustaining that in gameplay. My monitor is also a 120Hz G-Sync monitor, not that that should affect my PC's stability when running the game.