Not sure. I haven't read anything saying they have, but I wouldn't be surprised. Even if they did swap (as much as a dislike the company for doing it), the S11 Pro would still be as fast or faster than the sn550 and it costs $20 less right now.
I think the S11 Pro's are still okay.
I am also sure that they are not the only ones that swapped out mid product cycle. They were probably just the first ones that got caught doing it (much like the WD debacle). First getting caught usually gets burned at the stake even if the other companies have been doing the same thing for just as long.