Things were fine leading up to check-in. Hosts were good about communication with regards to possibly changing the reservation period. At check-in we found that the refrigerator was not working. We texted the host, and the fridge was fixed the next day. The place could have been a bit cleaner; we found some hairs in the shower, etc. but such issues were minor.

The main issue came with a dispute over the malfunctioning kitchen sink disposer. After dinner the last evening we washed the dishes and used the sink disposer. We had only flushed down soft foods like lettuce and rice. I'm not sure how the plumbing works but a pipe outlet at the side of the main door ejected all the food waste that had gone down the disposer. It was messy and unpleasant but I took a picture of the incident, sent it to the host to notify them and cleaned the mess up afterwards. I was initially not going to make a big issue about it in the review but a few days after our stay, I got a request pay for incurring damages on to the kitchen sink. The message from the host read that they had found damages in the sink and used the picture that I had taken of the incident to demonstrate the damage to me.
First, we only drained soft foods down the sink so it was unlikely that we had caused the issue. Secondly, how would one know whether the damage was caused by us or wear and tear by the residents who have used it so far? If they had found evidence of damages that was clearly done by us that's fine. But the evidence they used to state that I had incurred the damages was the picture that I took to notify them, that they had such an issue that they might want to address for future residents.
After I got the request for compensation for the damages, I explained to the host that this was not my responsibility and refused the request through Airbnb. I have gotten no responses back to my explainations to them and for my inquiry into theirs. I suppose they may say something now since I have made a public review. I'm not sure if this was a communication issue between the co-hosts, but I must say that it made a very unpleasant lasting impression of the place. To those looking for a place to stay while visiting San Francisco, I suggest you look elsewhere. There are plenty of places with similar quality and similar price.