User blog comment:TintinCT/The Magic Blackwater Church Glitch/@comment-10278667-20120822172705

I know exactly what you're talking about, though this has never happened to me anywhere but MacFarlane's Ranch.

In my experience, this strange pull has made "Obstacles in Our Path" deadly. There's this one bridge and every time I approach it at full speed, I'm suddenly pulled off to the side, causing my horse to run off the cliff, killing us both. I have failed that mission countless times thanks to oddity.