Control rig not applied when launching in standalone
Confirmed in 4.23 Main @ CL 5728426 (Differences in control rig nodes noticed in 4.23 (Executeable, ApplyFK not accessible via context menu, no input for Hierarchy))
Sample Project Attached
Result: Skeletal mesh will have arm separated when playing in PIE and Packaged Game, arm will not be separated when launching in standalone.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-72326 in the post.