UE 5.1 "Cook everything" option doesn't work

UE 5.1 refuses to cook everything and the editor “forgets” the option is set, even though it is saved to DefaultGame.ini.

  1. Open Editor, go to Project Settings | Packaging
  2. Close Editor
  3. DefaultGame.ini has “bCookAll=True” line added
  4. Open Editor again, go to Project Settings | Packaging

As a result it doesn’t package everything and I cannot make it do it, even though the ini was updated.