I need advice

I made a post here recently and received some great feedback. This one may be tmi but I need help.

I'm currently supervising a group of elementary children for an aftercare program. There's a 2nd grade girl who keeps scratching/touching her groin area and I'm not sure how to approach this. At first I just ignored it, thinking she was just readjusting underwear (a common thing to do and obviously kids are less discrete). But it's been about a month and she still does this constantly. Regardless of her outfit which is usually either skirt/spats and leggings. Thankfully she only does it over the fabric but with how 'breathable' they are I'm not sure how much better that is.

I'm male and didn't want to approach this directly so I brought it up with her teacher during the first week I noticed. I wanted to be aware of any health issues. Just enough info for someone in my position. The teacher called her over, the girl said she felt "itchy" and the teacher walked her to the bathroom. I didn't bring it up for weeks but still noticed her scratching regularly.

I will say now that if she were younger or male, I wouldn't hesitate to send them to the restroom. I may be overthinking it but I do want to be sensitive with matters like these. I'm cautious of any internalized misogyny from growing up as a boy in the south (USA) with only brothers may have caused. I don't want to tell her "that part of you is dirty, go wash your hands". Or call her out in front of her peers. Again, she's not discreet at all and I'm not familiar with this age group. It's so odd that scratching their crotch is acceptable but they complain their food is dirty when it directly touches the table...

I also brought it up with my supervisor more recently. She flat out told me that I shouldn't be dealing with this (to my relief) and said she would consult with the teachers. I'm confident a talk or two happened. I asked the teacher again last week and she said to just ask "do you need to use the restroom" when I notice the scratching. That she's smart enough to catch on to my meaning. It's only been a couple of days, but the girl isn't really picking up my message. I ask, she says no, I say bluntly "please go wash your hands", she replies "why?". Even when she's "in the act". Maybe I need to give it more time?

I didn't expect her to stop doing it immediately. Yet I can't tell if it's gotten worse or if I'm just noticing her doing it more. I loathe the idea of bringing it up to the parents, I'm not even sure if I'm allowed to.

Oh, I've been told by teachers and staff she has no medical reason for this behavior. Maybe I'm a being a germaphobe, but if it was a buttocks getting attention I wouldn't hesitate to send them to the bathroom and supervise handwashing.

I'm confident I'm not the right person to talk to her about this so I won't try. But it's too unsanitary for me to continue to ignore. Once or twice to "re-adjust" is fine, but it's been consistent. I feel like I'm indirectly enabling it by remaining silent. There are 4 other girls in her grade who do not do this so I'm fairly confident this isn't a general 'thing' for this age and sex. I know this wouldn't go unnoticed in later grades, but I figure they're all still very young and will learn soon enough.

How do I discourage this behavior, ideally indirectly? I'm more so concerned with hygiene and being sanitary that outright stopping it. she's still touching her friends, food and supplies after all. I'm positive this is a talk a parent should have ideally and have been hoping the teacher would bring it up to them. I don't plan on having any 'talks' with the students, but I don't want to continue to ignore this.