Was playing a game last night with the following settings Warlord/Tiny/Always war/OOC using Sitting Bull. Just playing a little defense. Went to upgrade my main city defender from rifleman to infantry and his XP reset. Went from 82/82 to 10/101. First suspected this when I upgraded that unit from a longbow to a rifleman. Wasn't watching careful enough to catch it then so i played til I could upgrade it to inf. Save is the turn that I upgraded the unit it shows its XP as 10/101. I checked the forum and the change list for 3.13 and saw no mention of this type of bug so I thought I'd throw this out there. If this is a "working as intended" design feature please ignore this post.