I had the same problem a while back with Solus and Peppermint 10. However, it wasn't Peppermint's fault, the fault was solely with Solus. Solus doesn't use GRUB for GPT partition schemes, it only uses GRUB for MBR partition schemes. So, Peppermint wasn't correctly seeing it because it was using some weird bootloader.
Now, I'm not saying that's what happened here. It looks like PCLinuxOS still uses GRUB. Unfortunately, I don't know enough about UEFI or GPT to hazard a guess. However, knowing that you're using UEFI and GPT may help others when trying to help.