Retraining bug?

[DVX BELLORVM]

It is a known bug, and a very annoying one. Don't save your game if you have anything in the recruit queue.

[Ramses II CP]

Very irritating bug. The only guaranteed way to fix it is to wait until the very end of your turn, remove all units from your recruitment queues in all of your cities, use a spy or other agent's abilities on the enemy which, I'm told, resets the seed, and then put your units back in the training queue. It's particularly prevalent and annoying when you have a Master Swordsmith and Horsebreeder's Guilds, but the English get pegged with it a lot too over the Woodsmen's Guild.