Appending action deforms armature

I stripped a BLEND file down to the basics (two rigged characters) to handoff to a freelancer, who created an action (animation sequence). The action looked perfect. When I appended the action back into the original BLEND file, some bones were deformed.

I had previously appended an action created in this manner with no problem. Any ideas what was different this time? I spent a long time looking for differences in the configuration settings but was unable to identify any difference.

Good:
image

Appended, Deformed hand bone (wrist bent back):

Good:

Appended, Deformed neck rotation (head facing wrong direction):

Good:
image

Appended, Deformed head and elbow: