FHA loan not allowing window units (even though they are brand new)

[Jon Cave]

So I bought my first flip in March and contractor was a nightmare. Got it all finished under budget after 4 months and got a buyer but the buyer is using an FHA loan. So, they required that I fix a few things then they came and did a SECOND appraisal and required that I fix more things including a new furnace which I had to have installed the midnight before closing. So, I closed Friday and the buyer was supposed to close today but now the lender is saying they want an entirely new AC system installed even though 4 brand new window units have been part of the deal all along. Have any of you seen this before? This project has been chipping away at my profit and dragging on and on. I wanted it gone before summer and now its August. Any insight is appreciated.