Yaarel
🇮🇱He-Mage
Which is the error?The shortened version on page 45 is most likely in error. The longer version exists in two different spots and is therefore, more likely due to the increased length AND more appearances. In any case, at best it's non-proficient due to page 45 AND taboo due to page 65 and 164(I think).
One place says the non-metal armor proficiency clearly.
The other place strangely uses a verb "will" instead of "do", a wording nonexistent anywhere else, but otherwise agrees: non-metal armor proficiency only.
The benefit of taking the clear statement as the intent is:
• The D&D rules are consistent.
• The D&D rules are normal. A class grants some proficiencies but not others. A character can get a proficiency from an other source.
• There is a mechanical penalty if lacking an armor proficiency, and this applies normally.
• The rules avoid weird interpretations that dont exist anywhere else that harm the game.