When mining compact skeleton ore with ore excavator when enigmatic legacy is installed, minecraft crashes.
This is specifically with compact skeleton ore: skeleton ore by itself or other compact ores are fine.

See Aizistral-Studios/Enigmatic-Legacy#31 for more info.

DoubleNegation did some further analysis here that you might want to check out:
Aizistral-Studios/Enigmatic-Legacy#31 (comment)

here's a fix (disables head drops):
funoresfix.datapack.zip

a better fix (no such thing as JSON comments):
funoresfix.datapack.zip