I've also been affected by this bug and just wanted to report my findings in case it is useful.
I have tested different versions of debian jenkins packages on our test/fallback jenkins instance with our production config, and I find that the bug appears with jenkins version 1.619
It does not appear in any jenkins version prior to that, and appears in all versions tested afterwards, up to and including 1.634
This pattern of behaviour is unchanged no matter which version of the dashboard-view plugin I use with the jenkins installation.
In particular, even the latest version of dashboard-view plugin (currently 2.9.6) does not produce the bug if it is installed with a version of jenkins at 1.618 or lower. This leads me to believe the bug may have been introduced into the main jenkins product rather that the dashboard-view plugin specifically.
I have two systems running, one without the bug and one with. I cannot see any obvious reason for the bug using firefox web developer tools, but I am not an experienced web front end developer. I am happy to test any theories that anyone might have about what is causing this.