Well it turns out that there were not any changes to the game. The food levy was not decreased. It is the same as it was. In fact it was increased from 10% to 20% just a few weeks ago, as documented in the patch notes.

Level 16 historic cities do not always have the exact same army composition guarding them. Once again, this was not a change. It's been that way. You just need to scout.

So there were no "silent" changes.