It depends how you evolved it. If you only made it so it had 2 evolutions then it will only have 2 PBs,
sometimes when you evolve them, you do get a physical change but no PB exchange. it depends on the pathing of evolution.. ( i built nothing but dex to 50 for all 3 PBs)
i was switching from dex and pow to get a twins PB and i needed to stay on the path of dex, and had there messed up.
i had a rukmin 153 2 PBs and i trashed it.