Thanks, guys!
It's funny, though. This post didn't really belong in this forum since I was experiencing it in SH5 and I put an edit up once I realized my mistake, but I've still got a bunch of answers here as opposed to none from the SH5 one.
Also, you're absolutely right. It's apparently something that carried over through the various new versions. Reloading did take the problem away, thanks!
Being an old Silent Hunter vet, it warms my heart to see that SH3 is still going strong because, let's face it, it's an awesome sim. I don't know how many hours, weeks, month, years I spent fiddling with that one and playing it like crazy, I even bought a new copy because I misplaced my original, and I still love to drag it out and dust it off.
Memories... Glorious memories.