As of version 3.0 the zen timestamp plugin appears to be no longer compatible with Hudson. I tested it in a stand alone Hudson instance (no additional plugins) against Hudson versions 2.2.0 and 2.1.0 and noticed that the BUILD_ID variable is not getting replaced by the correct pattern.

I rolled back to version 2.2 of the plugin which appears to still be compatible with both versions of Hudson above.

I did not see any errors in the logs when running projects with the plugin activated, only that the environment variable contained the original timestamp formatting.