She should have seen it coming once she found a job, but you can't really blame her or thousands of other people (including me) for not fully understanding how the program works.  

A Tax Court decision last week illustrated one of the anomalies of the formula for determining who gets the credit.  "George’s and Daniele’s MAGI was $91K. Their APTC was $23K. So being $8K over the limit gets them a $23K deficiency."  Blogged at

https://taishofflaw.com/2023/04/06/eightll-get-ya-23/