For Season of Discovery Phase 1, Professions are locked to a maximum skill of 150. Typically, Expert Profession Training would only require level 20 and a minimum of 125 Skill in the Profession.
But for Season of Discovery, you need Level 26!
This change limits the amount of overpowered items some professions could access. For example, many Engineering items only have profession requirements, but no level requirements, so a Gnome Engineer could have equipped Deepdive Helmet before the changes.