Was it found on the inspection? 

Very similar to their Premier Agent system.Zillow's instant offer is verified by a real estate agent who meets the seller and walks the property to verify condition (Zillow also does inspections to drop their price further if Seller accepts it) but the agent's goal is to take a listing by showing the seller how much more money they'd net, NOT to talk them into taking Zillow's offer.

I issued a draw to our HVAC/Plumbing contractor to get this project to the rough-in inspection. 

@Jonathan Barr it might be worth looking into properties where the inspection reports are provided upfront.

I would take the opportunity to ask them if there is any other maintenance issues, go over there, and do a full inspection.

Should we ask to skip inspection since they have been living in the house for 6 years?

If they are moving out, you do an inspection AFTER they have moved out documenting anything that is not normal wear and tear (take photos). 

I really want the property and I have a someone that can go look at it plus I will get it inspected. 

That's where they kept their weed and bong but forgot to take with them.Having a great move-in inspection check list will help on your move-out. 

Wisconsin also has laws on the book the prevent most mandatory landlord inspections.