Yes, this does happen, especially on foreclosed properties.

Typical scenario is that a lender forecloses on a property and wants to dump the property ASAP. They don’t like being in the real estate ownership/management business. They want to sell. A smart buyer makes a low-ball offer, but the lender needs an appraisal in order to do the sale. The appraiser comes up with “market” value, which may be higher than the low-ball offer. Here the lender pressures the appraiser to come in with a LOWER value so the sale can go through with no questions asked.

I once appraised a mobile home park that had some big problems, but was in a good area with very few housing options. There were successful mobile home parks in the area that were fully occupied. There was a lot of value in this troubled mobile home park, and my valuation reflected it. The lender wanted me to drop my value so he could do a quick sale. I said “No.”