There's something going on with these dual evap units, and Whirlpool is aware of it. Per Service Pointer W10666205A dtd March 2014:
Slow Ice/No Ice
Warmer than normal freezer temperature
Long/Constant run time
Partial frost pattern on the freezer evaporator
discoloration or deterioration of the refrigerator evaporator housing
Note: The first symptom a customer notices is usually a decrease in ice production followed by a noticeable temperature increase in freezer and longer than normal cooling cycles.
1. Verify the above symptoms with customer.
2. Check and record freezer, refrigerator and ice box temperatures.
3. Run tech sheet diagnostic test #4 (Compressor/Condenser fan/Evaporator fan) and #56 (I/M error codes) and record the results. Call the Techline (Authorized Servicers Only) from the customers home for further instructions.
Affected Serial Numbers: K217XXX - K335XXX
And Brother CubbieBear84 reports this:
We have scraped 3 of these fridges already. I've heard there's holes in the evap. Tech-line will record all the data and if it fits within their set criteria they give a concession number and send a new one.
Something to keep in mind if you're called out on one of these with a warm compartment complaint.
Source: model WRF989SDAF00 whirlpool frig.