@Keneda Just a few 2 cents her:

Yes for porting we often set the Android build to build a so-called userdebug image. That ensures certain behaivour, but I am unsure if we really need that. So it could be that the FP4 kernel built during our porting build is set to debug since userdebug target is being used.

Someone could explore this by trying to build their own port with instructions from porting group and then see which flag is being used. It would be good to finally address this, since debug kernels are potentially slower than release.

You could try this:

Link