If it was 1994, I could tell you all about cache configuration with an IDE interface and why you would never use write caching, especially if you also had an ATAPI drive...
Windows 3.1 is no longer with us, and neither is DOS 4.5 or whatever it was... my 3 1/2 inch game boot disk is no longer working either, and I no longer have to worry about properly configuring my Soundblaster 16 whatever it was...
Oh!, and let's not forget about PIO Modes etc...
But I never have trusted write caching. The computer OS decides when it's a good time to write to the drive, and an old game does not know that. However, if something goes wrong with a write like that, then ~all~ the loads would be corrupt. This is a re-load thang. What it reminds me of is similar to when a person runs the Museum, you cannot trust the game to run properly, and vice versa, if you run the game first, you will not be able to run the Museum. Something in SH4 is not "cleared" when swapping "modes", or whatever it is.
But then again, this is not that. We're not swapping "modes" (or whatever it is). All I can figure is that maybe FotRSU just has a lot of data to Save for the game, and when you do that 2nd load, it acts similar to changing modes??... I dunno. If that was the case though, it would happen every time, and it doesn't. I just got finished with FOTRS v2.0 (GE) for SH4 v1.4, and had no issues with the Balao on Jan 2, 1944 several times, so I went no further with it. Tomorrow, I'll do similar with Stock and GFO.
