I have been seeing a lot of incorrect completion times in barracks queue lately.
It seems to manifest when barracks is buffed and queue lasts longer than the buff. Verified and reproduced with skunk and training overtime buffs. It seems like the queue time is correct up to the last batch of troops produced under the buff then the next batch adds days or over a week and effects everything after it.
This has cost me some expensive and rare buffs as I thought I had an over ten day queue so I sold my soul for a rec. guide only to wake up to empty barracks next morning.
Here are screenshots of two batches of militia immediately after each other. Note the time remaining on the buff and the last correct training time.
7h0m.jpg
8d23h.jpg