Missing Skills

[SilverEX123]

Date & Time: 07/18/2019
World name: All worlds
Character name: All characters
Class/Level: All Classes and levels
Steps:
1. When playing as my Pugilist (Level 44, Conjurer (Level 31) and Arcanist (Level 16) characters, I noticed certain skills are unusable, such as the Conjurer's Protection spell, or Arcanist Energy Drain. I can't remember what was missing from the Pugilist because I already changed the unusable skills out for other class skills.

Question:
Is this a really glitch, or is this because I don't have any expansion packs, like the recent Shadowbringers? Are skills now dictated by which expansion pack I have?