to reproduce the issue, spawn a fairy with xaeros minimal and xaeoros world map installed. as soon as the fairy has a chance to register on the map, the game crashes.
crash-2021-08-24_16.34.52-client.txt

Ok, I see what's going on here - we've set the Fairy to have a null texture, due to it only rendering via particles rather than a standard mob entity, and Xaero's just doesn't think of that case (decent assumption to make, but ends up being wrong here). I hope they'll be willing to fix it, it'll be annoying for us to get things set back up on our side, but if not then I'll push through that.

I think we already have a transparent texture we can use

@murapix This is actually no longer an issue in the latest version of my minimap (for 1.12.2). They are using an old one.

@thexaero Thank you so much.