I was attempting to use the new levitation effect to create rocket boots (with some success). I did this by setting up three repeating command blocks. One would give the player levitation 2 (1, if they were looking up), one would give them levitation -2 (253, if they were looking down), and the other would give them levitation 0 to make them hover (255, if they were looking ahead). Each of these command blocks would only apply the effect for one second so one of the others could take over if the player changed their vertical rotation. What I was expecting to happen was for the player to float up if they looked up, hover if they looked ahead, and float down if they looked down. This was mostly successful, however, the machine would not go directly from floating up to hovering. The levitation 2 effect would not expire so the levitation 0 effect could take over. When looking at the command block feed, I could see that the levitation 2 effect was no longer being applied, but the levitation 0 effect was; despite this, I continued to ascend.

To replicate my exact conditions:
1. Place three repeating command blocks that are always active

• One must read: "effect @p[rxm=-20,rx=20] levitation 1 255 true"
• The second must read: "effect @p[rx=90,rxm=20] levitation 1 253 true"
• The third must read: "effect @p[rxm=-90,rx=-20] levitation 1 1 true"
  2. Look up to float up
  3. Look forward in an attempt to begin hovering
  4. Observe that you do not begin hovering, but continue to rise, despite the command block feed saying that you are being applied with levitation 255