Adam Riess might be right, but for reasons he won‘t like. Much of his measurements (and also his Noble prize) depend on the supernovae 1a, which according to the standard model are standard candles. That means it is assumed they always reach the same luminosity, so they can be used to measure distances in the universe (the fainter they are, the farther away they are).

However what if supernovae 1a are not standard candles and their luminosity varies over a much greater range? Then a lot of distance measurements from Riess et. al. are wrong. I belief that scenario to have higher probability than many of the proposed alternatives. But Riess cannot see that, because it would put into question his lifes work.