Agree completely, I already noticed these “A” entries in the past when searching for certain words on bunpro and they always confused me a bit.
Not only do they look like CEFR entries, they also don’t seem to count in the usual backward order that is used for the other decks, so A1 is the lowest of A decks, right?
Unless there’s a deeper rationale for these A names, I would strongly suggest changing the naming convention. Maybe something containing “N0” so that people understand where those decks sits in the current progression.
Obviously the best solution is just to use 大字 kanji because they look baller: N0-壱, N0-弐, N0-参.