Reproduction:

• Have a job that's triggered repeatedly by a timer.
• make sure there is no node to execute that job.
• Let the job sit in the build queue for some time.

Result: After some time the build queue hover of that stuck job might take up all visible space, because it contains all the failed time based triggers:

I suggest to remove all duplicate build causes (or whatever model elements those are), as they don't provide any benefit for the user.