Player can move while spectating a marker

The bug

When spectating a marker, the player is allowed to move. Occasionally, and seemingly randomly, the player will be teleported back to the location of the marker. Additionally, when the player changes their game mode, they will occasionally be teleported back to the location of the marker.

How to reproduce

1. Summon a marker:

   /summon marker

2. Enter spectator mode:

   /gamemode spectator

3. Spectate the marker:

   /spectate @e[type=minecraft:marker,limit=1,sort=nearest]

4. Attempt to move
   You are able to move, and may occasionally be moved back to the position of the marker