Heart Chocolate Box - Shattered pieces inside

Hi guys, Has anyone experienced anything similar to this? A Lego GWP Heart was on our shelf, in its stand, closed on display for some time. Opened up to show my daughter the chocolates inside, and I noticed discolourations on some pieces, then found a few pieces crumbled in my hand! Different pieces, different colours, and the rest of the red external box is fine. Other chocolate pieces also fine, just one with a few shattered pieces, and a long maroon tile split in half! I was thinking...