Did anyone else notice Ron's wig didn't look right?
I just did a side-by-side comparison and it was clearly a different wig than the one used in the first film.
The original was thicker and had more body (slightly wavy), while the one used in the sequel was darker, had no body, and was messier.
As a result, Ron's appearance looked off for most of the film.
Maybe the original wig was damaged or had gotten lost, but it's still the hair/makeup people's job to find a suitable replacement.