It is the Citric Acid that can sometimes be found with the canning items.
https://www.amazon.com/Ball-Jar-Citr.../dp/B007CRHD4U There are also special products made according to
https://www.consumerreports.org/dish...-a-dishwasher/ that are made specifically for cleaning dishwasher.
Janey - Neat people never make the exciting discoveries I do.