FBX bone scale export bug?

when exporting animations for game engines, I often only include the skeleton (unless I need shape key animation). but I’ve come across a weird issue. If the posed armature has any sort of scaling, the scale information will be discarded on export UNLESS I also export a mesh at the same time.

I can simply this issue to creating a single bone armature, scaled in pose mode, and a cube that is parented to the armature. the cube doesn’t even need to have any vertex group weighting. it just needs to exist as an armature driven mesh in the export. and this only seems to be necessary for bones with scaling.

Side note, I know to generally avoid any non uniform scaling because fbxs don’t deal with bone shearing etc. but this is a simple uniform scale (and it does export fine - just only when a mesh is included in the export for some reason)

so to recap: in the screenshot below, if I export just the armature, the scale on it is lost. but if I select the armature and the cube, the armature exports properly.

is this reasonably something that could be considered a bug, or some incredibly esoteric limitation of the fbx format? (ideally i don’t want to have to include redundant mesh data in all the various animation loops i export for a game)