So someone on Amtrak's Facebook page posted of picture an Acela meal that was described as "shrimp in lobster sauce." That seems to be a new dish - when I asked, the poster stated that the salmon dish was not on the menu (but the short ribs still were). I last traveled in first class two weeks ago and the menu was the same as it had been.
So it seems the menu has been refreshed very recently. I'll included the photo that was posted over on Facebook.