Hi!
I am fairly sure this is an issue with this mod. I just got it, and this happens with player spawned and naturally spawned horses (I only played in creative). When I right-click a horse with nothing in my hand (to ride it so that I can tame it) the game crashes. Exit code -1. The only info I could find on this code was that it's a PC issue, or a corrupted file. But it seems to be an issue with the mod, because I can still do other things in minecraft. However, every world I load into in which I have already right-clicked a horse and crashed, will crash my game again if I try to open it. I can create a new world and do everything other than trying to ride a horse.
I am really not sure what to do with this, but I appreciate your help and thank you for creating such a beautiful mod!

Tried a couple more things to see what happens. I can nametag a horse without issues. I am using the latest version of the mod. Here is the exact error/exit code

What Minecraft version is this on? The mod only supports versions up to 1.20.1

Someone else experienced this issue due to attempting to use the mod on Minecraft 1.20.4. I'm going to assume this is caused by the same problem, and have edited the mod so it will complain if it is loaded on an incompatible version. Will be doing version updates later, possibly once 1.21 is out.