The weekly-release-cron build failed due to some java 8 data/time methods needed to be white listed in the groovy security sandbox. Sadly, there is no jenkins "user" interface to automate setting these up as they are discovered in a testing env, or even a way to pre-emptively white list them before they cause a groovy sandbox failure. I thought this had been taken care of because nightly-release-cron was working but the tag generation is done slightly differently.
I'm going to leave this issue open until an upstream jenkins ticket has been opened requesting that the java8 date/time methods be added to the default whitelist.
There is also a problem with the saved state from tarball construction that can result in a subsequent build [re]pushing eups distrib tags from another build.