It's true, you can't make a group with a min ilevel higher than your own. But you can add an undergeared friend to the group and the same thing happens. When I see the "not qualified" warning, I hover over the premade to see the details and it usually shows that the min ilevel in the group matches what's seen in the listing, regardless of how high the actual requirement is.

From what I've seen, that happens because of the change that makes the "ilvl" column show the lowest ilevel of the people known to be in the raid group instead of the ilevel requirement set by the raid leader. For instance, if a 515 ilevel toon creates a premade with an ilevel requirement of 550, the premade will show up in the list as "515" instead of "550". My recommendation here is to change the displayed ilevel of the premade to be the actual requirement, but to use different colors to show the extra information, e.g. green 550 means the raid group's minimum ilevel exceeds 550 and red 550 means the premade requires 550 but there are people in the raid group that fall under that requirement.