jive.resource.salt = 2015-12-15
I think there were changes/fixes in 184.108.40.206 to do with resource loading and i18ns.
We also ended up setting these sys props to solve other i18n and Soy problems.
jive.resources.split.sub.soy.templates = false (this one solved issues we had overlaying certain core Soy files)
__jive.minify.soy.i18n.keys = false
Oh, and when I overlaid comments.soy in my build (220.127.116.11) it worked without throwing the error you've seen, possibly due to the sys props I've got set.. or maybe because we're on 18.104.22.168.