The 3 limiteds work well on FF.
Been using them on FF now for close to 2 years.
My FA77ltd don't display any PF beyond what would happen on any other fast lens in very high contrast situations.
Perhaps your focus is slightly off and that does accentuate it.
That said, CA correction in LR is generally pretty good nowadays.
I thought we already have in-camera distortion and CA correction on our Pentax Cameras? So I'm sure they will have that feature too in the FF since the FA limiteds are still considered current lenses.