Our solution contains peracetic acid, hydrogen peroxide, acetic acid, water, and cyclohexane and maleic acid? We did not measure significant quantities but polyethersulfone may be present as well. We're not expecting the maleic acid. What reactions would take place to create it?

What made this solution? The polyethersulfone sounds like a polymer degradation product. Could this be a source of maleic acid as well?

The polyethersulfone and cyclohexane may have been leached from the container the solution was in. The solution is actually a chemical disinfectant.