Ron VIRTUALLY DISAPPEARED!!!

I was playing this game again today, even though I already beat it. I was at the part where I was in the Carpe challenge and I was using Ron and Hermione after Harry got stuck. I was in the puzzle where you have to defeat the Hinkypunks and use Glacius/Lumos. So, I am Ron and I use Lumos on the first crystal ball. Once I do that, I switch to Hermione and I turn away from Ron to freeze the next waterfall so I can use the mirror above. I hear Ron behind Hermione grunt as he makes his way off of the ledge. I try switching to Ron and I can't. I turn to look for Ron...AND HE DISAPPEARED!!! I couldn't find him anywhere and couldn't do anything wothout him!! He...disappeared. Is this not weird or what?!?! I was like....WTF?!?! In the end, I had to shut my game off since I was sooooooo stuck and confused. I still can't make any sense of the damned thing!!!

JuSt WhIsTlE aNd I'lL cOmE rUnNiNg...I pRoMiSe<333