Its interesting because you have DD 89 which is almost identical to 86 in cover composition. There's 28 89s in 9.6 and up non qualified and ~76 total compared to 7 86s and 41 total. Go figure . It was a somewhat early Electro appearance so maybe that played into it? Doesn't explain #91 however. It implies the true high grade near mint census of 86 is quite higher than appears to be.
It's definitely weird. But after 20 years of CGC, I think the census is a pretty good representation of what's out there. I'd guess there are more high grade copies of DD 86 somewhere in the world. But a