Guy Sajer’s “Forgotten Soldier” - Truth, Fiction, or a mix of both?

After reading this one for the first time, it left a deep effect on me. It became one of my top 5 war memoirs. I was surprised to learn, after the fact, that the book is surrounded by a lot of controversy about minor details in his recollection or in the presentation of Sajer’s comrade’s names.

It is never fully stated to what degree certain recollections are fact or fiction (e.g., changing of names to protect identities).

It seems as though there are vocal swaths of people who claim it is totally fabricated, while others say it is intentionally a blend of fact and fiction, and still others say it’s simply a result of failed memory recall on the part of the author in some instances mixed with deliberate alteration of names/identities.

I haven’t located much in the way of the author addressing these allegations. Thoughts?