It's not super uncommon on multi-slot pets, especially when the breakpoint between 2 and 3 slots is mid-range. With nightmares the breakpoint is in a sweet spot at the bottom of the curve, so it's not uncommon to find 90-100% 2-slot nightmares. There can also sometimes be a bit of an overlap in intensity, if the pet naturally gained dex/stam/int/mana through combat after spawning, etc. That's why we put in a buffer for certain pets to account for this (which is why the intensity rating is showing it as an overcapped 2-slot, or a really poor 3-slot.).
In either case, that's a nice nightmare, and especially nice if it's a void color