All right - watched the article, and it's more about the likelihood of having an oral glucose load test being mis-interpreted while in Ketosis, or generally insulin sensitive, or fat-adapted, whatever your term of choice.
Someone who is deliberately keeping their insulin level low (as I am) in order to reverse T2DM, Fatty Liver, or pre-diabetes, will become more sensitive to insulin and sugar (this being the simple, and opposite of the biggest driver of insulin resistance, the less you have, the more sensitive you become).
So, being given a drink full of sugar, a person in this state will have a huge blood glucose spike, which may look like the kind of thing that would happen if you were insulin resistant - the difference being that it would not be accompanied by a similar spike in insulin.
We cannot easily test for insulin, so a doctor may interpret this wrongly... but I would hope that this would not lead to a diagnosis without a couple of HbA1c tests..