Node requirements are worded as “Requires Mage level 5”, when they should say something along the lines of “Requires 5 points in Mage tree”. As written, there’s significant potential for confusion because Mage refers to both the class and the tree, and Level refers to both character level and skill tree investment.
Based on the language and scenario in the screenshot, it’s completely reasonable for a new player to expect that he should be able to unlock this ability, since the wording of the requirement is exactly the same as the wording of the class info.
It’s because of the game being BETA. A lot of these nodes were resigned and move around a lot. A couple patches ago they redid the starter trees with new nodes which shifted everything; probably left from that. There is still a lot of errors in how many points you need to activate nodes and i’m not surprised this hasn’t been corrected. I would just report it as a bug.