Originally Posted by Niara
Yes, I'm sure. Being afflicted with prone, under any circumstance, counts as unconscious - it's currently baked into the prone condition, the way they've designed it.

Edit:

Quick screen capture on a fresh made game: this is my new wizard slipping on her own grease puddle, and losing concentration on her mage hand when the prone condition is applied, with a cut in of the tooltip for prone.

[Linked Image from i.imgur.com]

That makes it even worse. Thanks for sharing.