Teleporting an entity resets its Motion

The bug

When teleporting an entity using the /tp or the /teleport command, its Motion is reset to Motion:[0.0d,0.0d,0.0d].

How to reproduce

It happens with absolute and with relative coordinates. For example, put either of these commands in a repeating command block:

/tp @e[type=Zombie] ~ ~ ~1

/execute @e[type=Zombie] ~ ~ ~ /teleport @e[c=1] ~ ~ ~1

What I expected to happen was

The Zombie should be teleported one block further, then go down because of the gravity, then be teleported again, then go down, etc.

What actually happened was

The zombie was going in straight line without going down. It is the same if the zombie has a levitation effect, it won't go up because the teleportation resets its Motion.