Emulator

wild guess, but could you try messing with the Emulated CPU clock in Options -> Configuration -> Advanced?

JMC4789 wrote:

wild guess, but could you try messing with the Emulated CPU clock in Options -> Configuration -> Advanced?

That actually seemed to have done the trick. Putting the clock down to around 45 percent seems to solve the issue.
It's definitely caused by the frame rate being too high, as the issue occurred only when the fps was around 40, but lowering the cpu clock made it go down to 30 where the bug didn't occur.
The only issue now is the Sega intro is really laggy and load times took a huge hit but other than that I haven't run into anything game breaking yet.

Is there another way to lower the fps without causing lag in the intro and longer loading times, like an FPS cap or something?

Hi there, I can confirm that this bug exists. I've replicated it here: https://www.youtube.com/watch?v=k4r_YlQ2AFw (skip to 1:50 to observe the line getting cut off). This bug only affects cutscenes as far as I can tell and seems to be very consistent in where it causes the problems (the one at 1:50 is the earliest example in the game).

It's definitely caused by the frame rate being too high, as the issue occurred only when the fps was around 40, but lowering the cpu clock made it go down to 30 where the bug didn't occur.
I'm not certain, but I actually think the game actually might target 40fps on hardware for god knows what reason (though I don't currently have an easy way of testing this).

It's worth mentioning bug #12722 may be related which involved some skipping of dialogue (though in that case the problem was overly aggressive texture caching, fixed by tweaking a config)

Cheers