There has been a practice among appraisers that was always a bit odd. If a property is an "illegal use" then the property can not secure a conventional mortgage unless this is first cured. One of the most common examples of this are homes that are zoned single family, but have a second living space in the home that makes the home a multi family dwelling. In the past, I have seen appraisers/lenders call for the stove to be removed from this space, the appraiser comes back and takes a picture of the space with the stove gone, and... that's it.
No one is stupid enough to believe that actually "fixed" the issue, and Fannie Mae has finally made a public statement on the issue. That is not an adequate fix. In the video above the FNMA representative goes over how to cure these issues in illegal ADU's and multifamily set up:
1) The gas/electrical fixture must be removed
2) The gap of the cabinet must be covered over in a permanent fashion