No, it's when they get stuck in a sticky spot on their way to the lab.

There's a really bad sticky spot right behind the lab, for example, so I've had several bugs be dropped. All the bugs in question had appeared in the very center (right under the gong) of the cleared briars. The kids would go straight down from there, get stuck, and drop the item.

There's also a sticky spot next to one of the huts, which can sometimes get them when they're coming from the mosaic or from the direction of the wood pile.

It doesn't happen often, so it's not that big a deal, but I have had a rare bug be dropped... and I didn't have that bug yet!

I haven't had this happen at all in VV3 yet, so I'm hoping it was fixed.