I'm not sure if this has been posted here before, but I've seen similar reports on Reddit. Certain weapons cannot select between their alternative perk nodes. I'm not sure if this is an isolated issue with one weapon or perk. In my case, the weapon is The Hothead (Adept) and I cannot select between Demolitionist and Tracking Module in the 3rd column. Previously, I could freely select between the two perks depending on the type of content or boss encounters I was in.