The 1.16.100.58 beta changelog apparently said it fixed this issue in a change note stating:

"Removed legacy fall damage packet from client"

However, this is not true. I can easily reproduce the bug in the most recent beta (1.16.100.58). The fall damage sound plays along with the "floor hit" sound when a player lands on the ground but doesnt take fall damage.

Sometimes, though, I didn't even take fall damage. It seems to be random. This is the anomaly I reference in the title.

https://youtu.be/E_4u9PGKQBk

See the video above. 2 sounds play at once.