Current nightly builds have a severe regression against LTS.
As I do not monitor nightly regularly, I'm unable to provide exact version when it occurred, but quick scan suggests the root cause is move from gif icons to svg ones.
In LTS, when you the build is in queue, the "schedule" icon (the clocks) recognize this, and changes to be blinking (clock_anime.gif).
In nightly, the icon remains same, which enforces one more click from view to job to verify if the build is already queued.
Note, that the status icon behaves similarly - it shows last status, or moving last status if the job is already running.
From quick sca nit seems, that al the logic is already in jenkins, only identical icon is drawn, if the build is scheduled and in queue as if it is not in queue (not scheduled or running)
Note, that the icon do not change, if "build now" (the green arrow/clock.gif) is pressed. The change would happen only after reload given page