Ziploc Bags Frozen to Freezer Shelf

Why don't you put a rag in boiling/hot water and place it on bag near where it's stuck? Or pour hot water to separate and dry the area after.

I'd try a hair dryer. It works on car doors frozen shut.

Try mixing salt and hot water in a spray bottle, shake, and spray where the bag is frozen. Be sure to clean the saline solution off the fridge and baggie afterwards.

I would try hot tap water. A bit messy but you could pour it behind the bags of puree and that should melt the ice on the bottom.

Gently heat with a hair dryer? Or maybe try warm water.