It is possible to Glow Lichen to generate floating being unconnected/incorrectly.

As seen on the image, it should have been connected probably to the ceiling, but it is unconnected.

Seed: 5616051625065212617

Block coordinates: X=-608 Y=-6 Z=-232

Player coordinates: X=-609 Y=-8 Z=-232

Biome: minecraft:deep_lukewarm_ocean

Probably there are more specifications on the F3 debug screen. Thanks for seeing this report.