PRMC2285AF Freezer intermittently Stops

clean up

My fridge has an intermittent high-temperature warning in the freezer. I adopted this fridge from a previous owner about a year ago, so I don't have its full history. The issue is inconsistent — it comes and goes, sometimes correcting itself without any intervention. The onboard diagnostic UI isn't the most intuitive, but here's what I've tested so far:

• FZR Defrost Heater (diagnostic test 2) — Passed. Sensor temperature rose as expected when commanded on.
• FRZ Evaporator Fan Motor (diagnostic test 15) — Passed. Fan spins normally when commanded.
• Compressor — Turns on correctly via Freezer Boost (on prior attempts).
• Manual defrost cycle — Performed once; effect on the coil wasn't confirmed either way.
• Evaporator coil physical inspection — Attempted twice; couldn't get the back panel off to visually check for frost/ice buildup.

Any ideas on what it could be?