Sewer Line leak? Buy or pass?

[Cody Wirz]

I recently bought and fixed up a home that was built in 1986 in Dallas, Texas.  The buyer had an inspection where everything was good except they went above and beyond and did sewer line leak test.  There were no red flags to do this test, the buyer is just very thorough.  The test came back that there was a leak, but not one that would impact everyday usage.  Here is exactly what the report said, "

What should I do here?  The buyer wants to proceed, but wants me to locate exact point of leak.  I would be ok with this, but I have heard that doing pressurized tests on sewer lines, especially in older homes, is NOT recommend and could cause issues with the pipe.  There is no other signs of leak or impact of a leak, even the plumbing company said it likely a non-issue, but yes there is a leak.  Opinions?  Recommendations?