Thought this was a bug initially but is apparently intended, wanted to get the communities feeling about it. Currently UU Warriors (jaguars are the ones I noticed) upgrade to spears and not swords. This is so that the UU warriors don't upgrade into an iron requirement.
Personally I'd still rather they upgrade into swords, but I can see the appeal of guaranteeing they can be upgraded.
Personally I'd still rather they upgrade into swords, but I can see the appeal of guaranteeing they can be upgraded.