It's a common and stupid thing in mangas. Artists don't want the panties to show, because it'd be "too lewd", but still insist on doing upskirts, leading to making it looks like the girls are going commandos.
but hey, you can't blame them to show panties, right ?!
^Oh yeah sorry I should have clarified, the manga has been complete in Japan for awhile now, and the fan translation has been out for the last chapter on fan websites such as Mangadex for about half a year. The official translation is a good bit behind unfortunately, but that's generally how it goes I think.
I know exactly what you're talking about and I understand your pain, I thought these two would get a little more popular after that tidbit in Side Order
@Swag Wagon