Control rig forward solve function not working in packaged build

[KermanFooFoo]

For my UE 5.4 game, I’ve used largely procedural control rigs to both rig and animate characters. Part of this rig is a node which creates mirrored pairs of controls, so that I only need to affect one control to animate both parts of the model symmetrically.

Unfortunately, this doesn’t work in the packaged build (bottom of the video). The animation works mostly fine, but the mirroring simply doesn’t happen as it does in editor (top of video)

Thanks for any help.

(relevant parts of anim graph. The note says “source was visible but ignored”)

relevant part of the rig graph “apply wing control channels” lets me set the rotation of the wings using an input vector, rather than needing to work with the control transforms directly in the animation blueprint. The “forward solve array of mirrored controls” is parenting the wing bones to their controls, and then mirrors the control on the left based on the control on the right, using a custom mirror implementation, as the built in mirror function doesn’t work. I’ve tried changing the order of execution, but the problem persists.

[KermanFooFoo]

After further investigation, it turns out that the mirroring itself was running just fine, but that other, unrelated parts of the rig were throwing errors. Due to a typo, some of the control node names had inconsistent case when they were created, and since names are saved case-insensitively, this was not something I could address. However, the search function used in the “compare” and “contains” nodes is case sensitive, and needed to be manually overridden. A bug report has been filed.