I've harped on this a bit, but I think Buddy's return after sitting for Goodine was the best example of why the 40 minutes is never ideal.
When he came back in, his defense wasn't exactly a work of art, but he sold out on defense. The energy level was definitely kicked up a notch or two and I thought it was really noticeable.
I would guess part is likely because he had a blow, and knew he could just go 100% for that stretch to end the half. I'm sure part of it was also he was hitting shots, and players seem to get a lift on one end from good play on the other, but I do think we probably have a couple bad defenders made worse this year by the fact that they're conserving energy.