Minecraft version: 1.12.2
Wizardry version: 4.2.11

Question details: What is the purpose of replaceVanillaFallDamage? I understand with replacing fireballs if you want to add custom damage, but how is fall damage involved with this mod? Took me ages to track down this mod for getting random fall damage, and it seems way out of scope. I'm sure there's a reason, but for now I'm going to disable it. Could you maybe clarify in the config what the impact of disabling would be?

Thanks!

The vanilla falling damage calculation is based entirely on time in the air, and not velocity. This can result in taking massive amounts of damage if you're suspended in air for some time without that counter getting reset. A couple of the spells in Wizardry might trigger that, such as Grapple, so the mod provides an alternate falling damage formula that takes velocity into account.

Yep, that's exactly right. The system is a bit buggy (mostly on servers) so I would recommend turning it off if this keeps happening to you. The good news is that doing so will cause spells such as grapple to revert to a simpler method of just resetting the fall distance when used. This can be exploited to cancel fall damage if you try hard enough (although you can do that with a water bucket anyway) but it's better than having your legs broken every time you use flight, grapple or glide!