The 3 hour address validation fix that ate my whole Tuesday
Took me 6 weeks of customers getting refunds from the carrier to realize my checkout was passing the county name as the city, and now I just want to know if anyone else has had their plug-in quietly mangle addresses without any warning.
Worked at a place where the tax plugin decided every address in New Mexico was actually in Mexico. Just stripped the state code and moved on, no error, no flag. We found out when a guy in Albuquerque got charged duty fees on a t-shirt. Support kept telling him we don't ship out of the country and he kept sending screenshots of his own house. Took two months to trace it back to the plugin and the dev who built it had quit by then. Stuff like that never throws an error, it just quietly does the wrong thing forever.