Kibana should simply be showing the values of data.buildDuration as they exist in Elasticsearch. It's probably an issue with the Logstash config. If you query Elasticsearch directly for the values, do you see something else?
Alright, so the value in Elasticsearch is 461, and that's what you see in Kibana. This is what I was expecting to see. Something is not working the way you expect at the indexing stage. The value in Elasticsearch and the value in Kibana are the same, but it's not what you expected.
Maybe what the Logstash plugin is actually setting is the millisecond value? It doesn't seem to line up quite that way though. Maybe the value it records isn't supposed to correspond directly to the "sec" value you see in the build duration output?
Based on those variable names, it sounds like the buildDuration is in fact in milliseconds then. You can either convert it to another format, like seconds, at index time if you'd like, or you can use the duration field formatter in Kibana to make it show as seconds on the fly.