Our jobs are almost exclusively triggered by SCM changes. This way we avoid unnecessary builds of older releases or otherwise inactive branches. After upgrading from 1.602 to 1.604 on Monday, SCM triggered builds have stopped triggering.

This is not critical for nightly builds, as they are easy enough to set to periodical builds instead of SCM polling. However, for our continuous builds which poll regularly (more regularly than the actual build time), it's not really an option to set the builds to build periodically. Yes, the regularity could be lowered. But this could lead to a lot of failed build spam, if there are PMD issues or similar late one day.

After downgrading to 1.602, without downgrading plugins, builds started triggering again normally. I will retry with 1.605 in a few minutes, and see if this has been resolved in the latest release.