Example with no work teleport entity.

NotWorkEntityTeleport.cs

namespace VSExampleMods
{
    public class TrampolineMod : ModSystem
    {

        public override void Start(ICoreAPI api)
        {
            base.Start(api);
            api.RegisterBlockClass("trampoline", typeof(TrampolineBlock));

        }
    }
    public class TrampolineBlock : Block
    {
        public override void OnEntityCollide(IWorldAccessor world, Entity entity, BlockPos pos, BlockFacing facing,
            Vec3d collideSpeed, bool isImpact)
        {
            entity.TeleportTo(entity.Pos.AsBlockPos.UpCopy().ToVec3d().Add(0.5, 0.5, 0.5));
        }
    }
}