At some builds the build duration time seems to be wrongly calculated: http://ci.guix.gnu.org/build/1672744/details -> 1568730254 seconds which seems like unix time stamp for the finished time: Tue 17 Sep 16:24:14 CEST 2019
Some times it's correct, 11 seconds: http://ci.guix.gnu.org/build/1024003/details
