When the server's processing time drops below normal levels, players may experience unexpected fall damage in the following scenarios:

• Standing on ghost blocks.
• Bridging upwards.
• Jumping on normal ground.

also, players who have walked on a number of ghost blocks 10+ and then walk to real ground may suddenly take fatal fall damage even though their y position hasn't changed and after get the fall damage sound effect. truly strange, this also can happen on single player. Regardless of device. but more often on weaker devices

This issue appears to happen randomly and may be related to performance of the server