I went thru something like this as well, and posted about it yesterday. I had a female villager who was a master scientist, master farmer, and had the same amount of skill in building but was still adept. It took 2 days of being adept before she finally reached master and elder status. Just hang in there. Apparently the bar fills up in segments, and it's not til it gets thru a certain segment that they master. Good luck!
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Drop that laundry and get me tech points!