Recently I updated my Lightroom Classic on my MacMini M1 from 11.31 to 11.4, then I found that the flat-field correction does not acctully work anymore. (I use Leica M240 with SuperAngulon 21mm)
I did that step by step for many times, I could click the button and the loading bar also run, but the photos changed nothing. I reinstalled the version 11.31 today and it worked, then I tried to install version 11.4 and it didn't work again. So I think it might be a bug of 11.4 either on all computers or on Mac.