Why does my fridge keep freezing the produce drawer while the butter stays soft?

Yeah, there's literally a damper right above the crisper drawers on most of these Gallery models. It's a little flap door that opens and closes to meter cold air coming down from the freezer side. When they stick open, the drawer under it becomes a blast chiller while the rest of the box stays normal, which is exactly the split you're describing. On mine it was a jammed damper motor. You can usually pull the rear panel in the fridge section and watch whether the flap actually closes when you crank the fridge temp to its coldest setting. If it just sits there, that's your culprit. The motor assembly is a cheap part and swaps out with a screwdriver. Before you go that far though, check the thermistor, which is the little temp sensor clipped near the evaporator or in the fresh food section depending on the model. A drifting sensor makes the control board think the fridge is warmer than it is, so it runs the fan longer and dumps extra cold air down that duct. That would also explain your milk feeling different day to day. You can test it with a multimeter by unplugging it and checking resistance at room temp, or just swap it since they're usually under twenty bucks. One more thing people miss. On a lot of these, the control board has a bug where it runs the damper based on freezer demand, so if your freezer is set super cold, the fridge side eats the overflow. If your freezer is cranked down, bring it back to normal and give it a couple days before buying parts.

Six years is about when these things start acting up, so it's not just old fridge nonsense, it's an actual part failing. Worst case it's the main board, but I'd bet on the damper motor or thermistor before anything expensive.

Worth adding that on these the flap can be wedged open by frost, not just a dead motor. I work on fridges for a living, probably a dozen service calls a month turn out to be ice jamming that little door. If the motor clicks and tries to move but the flap stays put, chip the frost off or just leave the fridge unplugged with the doors open overnight and see if it frees up. Costs nothing before you order parts. Also wiggle the whole drawer assembly while you're in there, a cracked drawer track can let it sit a half inch too far forward right under that cold air duct.

So glad I found this thread before I started buying random parts. Mine did the same thing last winter, salad drawer turning into a freezer while the eggs on the top shelf were fine. I did the overnight doors-open trick and it acutally helped for a few weeks, which makes me think mine is the frost thing too. I also noticed the rubber seal on the fridge door has a soft spot where it doesn't bounce back anymore, so I'm wondering if warm humid air sneaking in is what keeps making the frost in the first place. When you pull that inside back panel off, do the clips just pry out or is there a trick to it? I don't want to snap anything.

Same saga here a couple summers back, except mine was the milk freezing while the produce was fine. What actually cracked the case for me was one of those cheap fridge thermometers, the kind that just sits on a shelf. I moved it around over a few days and mapped out the cold spots instead of guessing, turned out everything near the back left wall was running way colder than the dial suggested. Turned out my issue was the fan gasket had shrunk and was leaking cold air sideways, but the thermometer is what proved it wasn't in my head. Might be worth doing that before you tear panels off, since it'll tell you if the whole box is drifting or just that one drawer.

Update: I pulled the drawer out and looked up top like the repair guy described, and sure enough there's a flap back there with a chunk of frost on the edge of it. I did the doors-open overnight thing and the lettuce made it a whole week without freezing this time. But now I'm wondering, if it iced up once, is that a sign the defrost cycle is on its way out too, or does it just happen sometimes?