Switching from Spectator to Survival causes player death by fall from low height

What I expected to happen was...:
When three or four blocks above ground (not water), switching from spectator mode to survival mode, I should drop to the ground with no or minimal damage.

What actually happened was...:
Death by fall

Steps to Reproduce:
1. Not sure yet as the problem is intermittent. Generally flying around in spectator mode, above and below ground then moving to a previously visited area and switching to survival mode triggers the bug. Will need to do more research once my wife returns home. This happens to her occasionally, but not to me. She is running vanilla 1.9.2, but I believe it also happens in previous 1.9 versions and 1.8.9.

Just happened on Realms in a new 1.13 world.  Wishing I had started recording.  Drop was 3 blocks.