I was fighting some toy ventari over a gift and had to switch to my medkit to drop bandages for myself. When I switched, my medkit detached and was floating in the air. After kit swapping, my medkit appeared on my back again, but the original is still hanging there, defying gravity.
Also, Mad Memoires: Complete Edition continues to burn when you switch to kits that appear on your back, making them appear to be on fire. Same with using tonics, the fire almost always stays with you.
After some testing, I realized you can duplicate the hanging medkit by using a tonic with the kit active, and it seems to only work with the medkit, not the flamethrower or elixer gun. I ran out of tonics before I could test any of the others. I wasn’t using a tonic when it happened the first time, however.
edit: You can also see my pants clipping through the back of my boots in the first image. Bugs galore! The pants are Heritage Legguards, the boots are Noble Boots. The pants’ belt and uh, crotch, also clips through the vest of my Noble Coat but that isn’t visible.