No, it’s an equipment shortage. Amtrak VP Harris said as much during his comments to RPA. Reading between the lines, Amtrak didn’t expect to be running many long distance trains in the future, so many cars were placed in storage and maintenance was deferred.It is normal for the 2nd sleeper to appear and disappear from one day to the next in shoulder season. In winter it is usually absent.
The 2nd Seattle coach runs somewhat less often than the 2nd Seattle sleeper -- in a pre-covid year it ran most of the summer, but essentially never in winter or shoulder season -- but this year is the only year where I didn't see a 2nd Seattle coach all summer.
I am not 100% sure it is an equipment shortage and not just simple capacity needs...east of Spokane that still gives the Builder 3 coaches. There will just be a lot of people holding tickets reading "27" rather than "7".