No, within the Apple ecosystem the interfaces are normed - thus, no matter which Apple PCIe SSD you fit into the adapter, physically it should match. I have testet all three adapters with a variety of SSDs (OEM Toshiba, Sandisk and Samsung), they all work with the sole exception noted in my previous posts.
Unfortunately I have no SSUBX card at hand and I don't plan on getting one. The simple reason is that for my workflows there is little difference even between a SATA III SSD and a PCIe one.
Thanks, if no one else chimes in on this with additional info. in the next few days, I'll grab one and test it with my 512GB SSUBX and see what happens.