This bug is the same as https://issues.jenkins-ci.org/browse/JENKINS-15747 but it happens for us with Jenkins version 1.548 again (while it was working in the mean time).

In cases where there are multiple paths though the ob dependencies logging all upstream causes generates a huge build log.
The example job linked with this ticket has a log which is nearly 110MB in size because of that.

In the previous ticket the issue has been addressed by "not only cap total number of transitive upstream causes but also avoid redundantly storing information about upstream causes listed elsewhere".