20% GF PP Warp

[Pilot]

is this warpage presented also on short shots parts?

[joeprocess]

As others have mentioned you have proven that the fibrous filler is the true root cause. Not a whole lot of processing around this issue especially with what I see as the parts design. If talc or glass beads are not a permanent option perhaps a talc/glass combination may help reduce warp.

Can gussets be added to the outside of the part to tie the flange to the intersecting walls? If so you would want to make sure to not make them too thick or it could make the issue worse. I've seen adding gussets at about 50% nominal wall thickness help with this type of warp.