Garrison bug?

[flipflopfloop]

I was switching my garrison units when all of a sudden none of my units could be garrisoned, and moving any of my previously garrisoned units immediatly causes me to switch units.

Is this a known bug?

EDIT: NVM I guess I goofed because I didn't know that sometimes when you direct your unit to move to a city they automatically garrison. Strange though, I don't remember such a feature being in the game before.