Elytra tp's you back when on a Server

When gliding with the Elytra players are getting lagged back
also the Elytra loses its Velocity so players cant glide far.
Setting Flying to true doesn't change that.
Server gets Errors like this
[01:28:02] [Server thread/WARN]: Flaxify moved too quickly! -
0.6657130139879399,-10.204714545798453,1.1101927266788039