"Fleetwood Mac In Chicago" - Not A Regular Studio Album?

[Rubber Duck]

Here´s what the credits say (from The Complete Blue Horizon Sessions box):

Red Hot Jam - without Danny

I Can´t Hold Out - without Peter, without John

I Got The Blues - with Peter, with John


And I agree with your friend, it was not regarded as a "proper" FM album at the time - and to me, it still isn´t.