An easy one, just to remind you you always have to be cautious. Here, white just played 31. Rc7?? in response to black 30. ... Rd6, lured by the undefended pawns...
I think it's funny when people add question marks to their annotations, like it's a on scale from 1 mark (Huh?) to 5 marks (WOW....WHAT AN IDIOT.......).