Has anyone else had this problem?

I'm finding that the lens profiles in Light room are playing up - sometimes they are there for use on some images, others not.
I know that the lens I've used has a profile (its available in a drop-down menu in some images) but then in others it doesnt automatically come up as an option, and even trying to select it manually, the 'make' section only lists Apple, Canon, Nikon, Sigma, Sony or Tamron - no Pentax (even though its in the EXIF, AND Ive definitely had the lens come up as an option in the same session but on another image)

Really cant work out what's going on or whether Im missing something.