I did a home inspection on a flipped home where they had a licensed master plumber but in a new bathroom. I hit them on the S-trap under the bathroom sink (first picture). The agent asked to have the S-trap changed to a P trap. The second picture shows it is now an S trap with a vent. I also reported the vent stack is too short because it's below the drain flange.
By the way. They could have used a regular plumbing vent through the roof but they didn't.
Can somebody tell me if this plumber is all washed up?