The Bug

When flying downwards towards a Sculk Sensor, it may emit a signal strength of 1 instead of 5.

Steps to Reproduce

1. Equip yourself with Elytra.
2. Place a Sculk Sensor with a Command Block connected to it (note: "x y z" must be set as the Sculk Sensor's coordinates):

   tellraw @a {"nbt":"last_vibration_frequency","block":"x y z"}

3. Get to an elevated enough position above the Sculk Sensor where you'd take fall damage if you were to walk off.
4. Jump or walk off into the ground next to the Sculk Sensor while holding w in the air and space to activate the Elytra.
5. Look in chat and note whether the message says 1 (issue) or 5 (expected behavior). There's also a chance that it will say 4, which would correspond to the event elytra_free_fall.

Observed Result

The signal strength was 1.

Expected Result

The signal strength would be 5.

Note

It's worth noting that walking off (pressing w until you fall off the platform) will tend to yield 1 more often when compared to suddenly starting to fall (breaking the block below you or stopping your creative flight).
This test yielding 4 could either be considered an issue on its own or simply that the Sculk Sensor happened to detect that event before the others. This may need several attempts to reproduce, so please be patient when testing.