Have been doing Lilith many times for other people, never had issues.
First time today 2 people (me and the other) both with Shroud of False Death, she suddenly got bugged af.

1) She does not aggro even if it's a boss so she gets stuck outside the ring (not sure about this being normal or not, in most of games invisibility does not work with bosses)
2) Annoying AF, thorns interactions are bugged so they start delayed, don't start at all, start "broken" (2 stripes instead of 3), it even happened that they started double lol.

TLDR: MAKE SURE AT LEAST ONE PLAYER IS NOT WEARING SHROUD OF FALSE DEATH OR ENJOY BUGS CINEMA