I think this is what he's talking about.
https://www.xbox.com/play/media/Bp3Te8bEPe
In the clip, I first backskate and let go of both the left stick and LT and my player glides all the way to the blueline. On the second try, I backskate and let go of the left stick and continue holding LT. On the second try, my skater stops skating almost instantly.
I don't recall this being an issue in 24. In that game, I believe you could hold LT to backskate while gliding without issue. I would assume this issue is due to a conflict with the new vision control mechanic, if I had to guess.
Edit: I did some testing and this is what I've found.
If your team has the puck, or the puck is loose but your team last had it, then holding LT won't let you glide: https://www.xbox.com/play/media/TFBxJFufEB (skip to about 20 seconds)
Alternatively, if the other team has the puck, you can hold LT and glide without issue: https://www.xbox.com/play/media/KrNmzyR5y2
Now, if your player has the puck, you can't glide at all after backskating. You also can't glide forward while holding LT. You can, however, glide forward if you let go of both the left stick and LT: https://www.xbox.com/play/media/42aKib4BHu