I have grown B. acaulis. That is not acaulis. I am leaning towards parkinsonianum at around 98% certainty.
I had the honor of judging a great Epidendrum parkinsonianum once at a Greater New York Orchid Show back in the 90’s. It came in on a huge piece of cork bark hung on a wooden easel. It was a good 18” wide and better then four feet tall. The leaves were long and cascading downward. It was full of flowers and looked like a living painting.
The leaves were folded lengthwise in half and they featured a very thin, papery covering to the base of the leaf. You can see both of those points in the very first image presented.
Brassavola acaulis has a cascading growth habit as well, but the pseudobulbs are rat tail like, very rigid and almost perfectly round. Towards the base of the leaf, the leaf presents itself with a little groove running from the bulb to a point on the leaf where it fades away. This groove, is kind of like where the very succulent leaf rolls inward in to itself creating this rat-tailed like appearance.
Those leaves in the very first image are clearly not rat tail like.