not needed

src/main/java/carpet/mixins/PlayerEntity_horseFixMixin.java

@@ -6,6 +6,7 @@ import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityType;
 import net.minecraft.entity.mob.MobEntity;
 import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.server.network.ServerPlayerEntity;
 import net.minecraft.server.world.ServerWorld;
 import net.minecraft.util.ActionResult;
 import net.minecraft.util.Hand;
@@ -37,6 +38,8 @@ public abstract class PlayerEntity_horseFixMixin extends Entity
             if (!getEntityWorld().isClient)
             {
                 ((ServerWorld) getEntityWorld()).method_14178().sendToNearbyPlayers(this, new EntityPositionS2CPacket(getVehicle()));
+                // not sure if player at this point is actually considered to be next to the exiting vehicle
+                ((ServerPlayerEntity)(Object)this).networkHandler.sendPacket(new EntityPositionS2CPacket(getVehicle()));
             }
         }
     }