Theoretically, the cpp code of your actor / stuff could be doing something different with an #ifDebug or similar statement that’s then being skipped when you publish as shipping.
Other than that
I’m not aware of any other issue, but you should do a test by publishing a default template / and or just your character BP within a new empty project.
That said.
What is normally used to shift your arms forward?
It sounds to me more like a bad Ik implementation than an animation issue…