Problem getting variable from Control Rig in built project.

I’m using the standard Control Rig (Legs IK) from the standard Third Person pack in Unreal Engine 5.
I need to get data from variable from Rig Control to Blueprint, so I use the “Get Variable as String” function and while playing in the engine itself and in Standalone mode, this works as it should, but in the built project (no matter Shipping or Development) this function stops producing any values, although all references to variables are relevant in the built project.
What could be the problem?
I suspect this can be fixed by some tweak in Project Settings or something similar?
Once again I repeat that in a NOT BUILT project everything works fine, in a BUILT project the function does not produce any values, although in both cases all the links needed for this function are relevant.

I would be very grateful for any help or hint!

I know that variables can be retrieved using Cast to the desired Control Rig, but I would like to know for the future what the problem with this function in the built project may be, because thanks to it you can pull out any variable without doing cast on the Control Rig.