The game already ran fine at 60fps (and above) on PC at launch, so the engine can handle it fine already.
"FPS Boost" is just marketing speak for "we've decided to prioritize framerate on the next gen consoles rather than improving visuals and keeping things locked at 30fps"
My theory is that it detects a list of certain compatible games and then "lies" to the game engine through syscalls for clocks or vsync or whatever the game uses to determine frame timings (this would trick a game locked at 30 to run at 60, for example).
If this is indeed how it works, it could well break other things that relied on those timing systems, like the scripted events you're describing.
As we detailed in October, with the increased CPU, GPU and memory from our new consoles, all of your existing games look and play better. With certain titles, we can make the experience even better, all with no work required by the developer, and no update needed by the gamer. To that end, the backward compatibility team has developed FPS Boost, which employs a variety of new methods for nearly doubling (and in a few instances, quadrupling) the original framerate on select titles. ... And while not applicable to all games, these new techniques can push game engines to render more quickly for a buttery smooth experience beyond what the original game might have delivered due to the capabilities of the hardware at the time.
It clearly distinguishes "with the increased CPU, GPU and memory from our new consoles, all of your existing games look and play better" from "FPS Boost, which employs a variety of new methods for nearly doubling (and in a few instances, quadrupling) the original framerate on select titles". Further, FPS Boost has to be manually
IANAL but it seems like offering a feature and blatantly lying about it is fraud and that everyone who participated at Microsoft is guilty of both fraud and conspiracy to commit fraud. Do you have evidence of this?
Here's more information: https://www.youtube.com/watch?v=89L-3U2egKw
.. completely common in the industry, especially when it comes to explaining how things work internally.
You might have a case if the 60fps game was actually running at 30fps and just lied to the frame counter.