The guys repaired a 4" main line leak under a concrete sidewalk while I was gone and Leo saved the "leak" for me which occurred at a SCH 40 glued bell joint. Since I had the time I cut the bell open to investigate the leak and here's some pictures of what I found. I've glued a new 4" fitting together (didn't have an extra bell and bevelled end so just glued together a coupling) and will tear it apart sometime next week to compare to this one. I'm not sure if it was glue failure or what. Any ideas?