It's the same rule that makes the Pole Vault Summit no longer count for DI qualifying. Although there are 50+ pole vault competitions held there, as far as the NCAA is concerned, it's 9 other events short.
The college coaches should have known better, the burden is on them to know if their athletes are going to countable meets. As mentioned in the article, Boston has had trouble with this in the past, so the college coaches should have known to check.
I think it's dumb, I think both the PV Summit and Boston are obviously very legitimate events and they both should count. I think the NCAA should allow meets to apply for waivers to the rule, and events that have college competitions as part of a broader schedule and that have a history of being run properly should be granted waivers. I think this is how it used to be done? I don't think it's a new rule, but I think they changed how they enforced it a few years ago. Or maybe it is a new rule *shrug*