This is a legal question at its core, so the direct answer is: talk to a real estate attorney in your state before signing any JV agreement or blasting a deal on behalf of another wholesaler. That one sentence is the most useful thing I can say about the liability question specifically.
What I can explain is how the structure works and why it creates this exposure.
A JV agreement (joint venture agreement) is the contract between the dispo partner and the contract seller that defines who does what and who is responsible for what. When the dispo partner sends marketing materials, including the seller's numbers and property description, to end buyers, they are often treated as having adopted those representations. Whether they "knew or should have known" something was wrong depends partly on what the JV agreement required them to verify before marketing.
Some JV agreements shift all liability for representations to the contract seller. Others are silent on the point, which leaves a dispo partner exposed when a buyer later argues the marketing email was misleading. The $19k repair overrun on a $28k assignment fee is exactly the size of dispute that ends up in mediation or court, so the agreement language matters a great deal.
The one thing worth raising with an attorney before you structure any deal this way: ask specifically about an indemnification clause. Indemnification means one party agrees to cover the other's losses if a specific problem occurs. A well-drafted clause can define exactly which party owns the risk when property condition turns out to be different from what was represented.
Everything here is a starting point for your own research and not a substitute for licensed legal advice.
What does your current JV template say about who is responsible for the accuracy of marketing materials, if anything?