So there is more talk about this in the lcd-x thread over here: 🔶 Audeze LCD-X - #309 by Souldriver
Its not that they had eq issues but instead their frequency response was off kilter to something like the harmon curve. EQing was suggested to reign them back in and in general reports say they take eq well.
I had Audeze send me the FR charts for my pair and they look much “more normal” than others and its an older pair. I may have lucked out as some older years also had a bit more driver variance that didnt help help the fr reputation.
It seems like the newest revisions are to help consistency and normalize fr, mostly. Not sure if technicalities were altered.