Night Fae players can no longer see the Heart of the Forest after completing “Winter’s Sigil” during the 9.1 campaign. It’s present during the cutscene where you return Sister’s Tear, but missing after the cutscene plays.
Other covenant players can visit and can see the restored Heart of the Forest, but for Night Fae players it’s both invisible and has no collision, the pedestal it normally sits above is completely empty.