Greetings.  Bill Sharkey has a problem with keys not moving when
playing rolls;  noting that this particular player has no keylock,
eliminating that possibility.  I hope this may be of help!

Are the keypins (front and/or center) rusty or corroded?

How about the key bushings themselves: are they swollen from damp
weather conditions, or have they been replaced and still a bit too
snug?  The center pin hole drilling itself may also be swollen enough
to hold the key stationary yet move freely when depressed.

Most likely though could be that the entire keybed has somehow been
altered from its original position.  Maybe the frame was shimmed at
sometime or it could be something as simple as keyfelt punchings
(felt and/or leveling punchings) being too many or too thick!  Unless
the piano is practically laying on its backposts and is reasonably
level, I'm sure the cause is one of the above.  And easily remedied
once diagnosed; a closer look and some experimentation should yield
a solution.

One more thought:  has some ham-fisted tuner screwed down a bunch of
lead weight to the back of the keys?  Any lead at all fastened with
screws (or even worse, nails!) is almost certainly not "factory."
That would definitely cause the symptom Bill described!

G'night Gracie,
Eric J. Shoemaker