I found this similar issue https://github.com/FasterXML/jackson-modules-java8/issues/165 but it seems different, as that user reported a bug on `2.10.2` and refers to a different config option. `WRITE_DURATIONS_AS_TIMESTAMPS` defaults to true. ### Before v2.12.0 `WRITE_DURATIONS_AS_TIMESTAMPS` set to true. It seems that a negative value... * Serializes incorrectly ❌ * Deserializes back to the original value ✅ ### v2.12.0 and later (including 2.18.2) `WRITE_DURATIONS_AS_TIMESTAMPS` set to true. It seems that a negative value... * Serializes correctly ✅ * Deserializes incorrectly ❌ Here is an example repo demonstrating the problem https://github.com/jmuia/jackson-duration-serialization