I almost posted my own thread about this last night. Good to see I'm not alone. I was going through the Noob trials and just could not consistently get the enhanced teleport for the life of me.
I appreciate that NRS is trying to keep the legacy input for the move, but D,U is a nightmare when it comes to enhancing it. They either need to allow it work like it did in MK11 (hitting the enhance button after you've already inputted the initial motion) or just changing the input outright.