Any issue to boil unpeeled potatoes and peel them after?

I steam mine in a steamer basket, cut up & unpeeled along with unpeeled garlic cloves. I drain them & put them back in the pot briefly to dry them off. Then, I run then through the ricer & all the skins come off & the potatoes are fluffy. I add in warm dairy in the warm pot. Easy.

I didn't test this recipe with unpeeled potatoes—I personally think it's much easier to work with them when they're peeled (otherwise you're handling hot spuds!)

I am in the peel after cooking camp, I'm afraid. I'm also not a fan of boiling spuds for mashing either. I find peeled potatoes boiled in water kind of watery afterwards, with extra liquid diluting the mash. I prefer to bake mine, in the jackets, and peel afterwards. For fluffy potatoes, I also use a ricer, not a masher and not a hand-held mixer, and add in the hot dairy/butter mix once they are all riced.

You could peel them after but when making mashed potatoes, it’s helpful to peel them in advance so the potatoes absorb some of the cooking liquid, which helps the resulting mash stay fluffier in my experience.