MainStage expression transform function not working

Dear community!

I'm using MainStage 4.3.1 and Sequoia 15.7.7 on a M1 MacBook Pro 2021. I recently got a minor problem with the expression function in the midi input window. When output controller is set to expression (regardless which input controller I choose) the transform function doesn't apply at all. It doesn't matter if I change the range or invert the curve, the expression knob on activated channels still goes from 0-127. No difference using expression-mapping in concert-mode or on a patch. Have reinstalled MainStage, updated preferences and caches files. Tried different keyboards and pedals. Same result every time. My workaround, for now, is converting expression to volume but that has some downsides, I think. Any ideas how to solve it or do I have to wait for another MainStage-update? Don't want to upgrade my OS yet because of some third-party plug-ins.