Empyreal signs crashing client

[Bobmcooper]

What's the issue you encountered?

I upgraded my server and client from 1.21.1 to 1.21.4 three days ago. Prior to that time, I had placed a few empyreal signs to prevent water from flowing out of one space to another (if it matters, they were placed on amethyst blocks in a mystic grove biome). Today, I returned to that location, and my client crashed immediately.

After several reloads and a server reboot, I was able to clearly establish that it was happening whenever I was looking towards one of the empyreal signs. Just turning towards it would cause a crash.

I set up an experiement to confirm it, and it happened immediately upon placing the sign. I had another player on site, facing the opposite direction, who fixed the issue by blowing up the sign with TNT while NOT looking at it (previously rigged via redstone). This problem does not seem to be affecting any other sign types I am aware of (I tested with Spruce, then Umbran, with no consequences).

I was ultimately able to use the /fill command to replace all my empyreal signs with umbran signs, fixing the location in my game, but wanted to report the issue so you can fix the empyreal sign.

How can the issue be reproduced?

Place, or look at an existing, empyreal sign. Will cause a client crash.

Logs

https://gist.github.com/Bobmcooper/45654295fe3b59972146b1200206a98a.js

Mod Version

1.21.4-21.4.0.20

Additional information

Can't say enough how much I thoroughly enjoy Biomes o' Plenty. Thanks for looking into this bug.