Someone goes into the freezer (part of refrig), "closes" the door, leaves the room, etc.
Too much stuff in freezer, or not correctly arranged, or whatever -- of course door doesn't close 100%, or does for a few minutes then pushes open a wee bit.
Maybe not noticed until next morning (by me!)
Obvious answer: get rid of some of the contents.
Heck, maybe all of it, or at least the meat -- since temp clearly not 0 or 5F where it should be, not with door not sealed closed.
Yeah, nice idea. Don't buy so much frozen food, etc.
Well, let's not pursue that particular track, huh. :-)
(Parkinson's law of freezer-space obtains here in this house!)