If a unit fails to complete a queued garrison order (e.g. because the garrison holder is full) and the next order in the queue is a "combat" order (e.g. kill a chicken), the unit will enter a bizarre state throwing errors like this on every order given to the unit thereafter (even after the queue has been executed):

ERROR: Tried to process unhandled event 'Timer' in state 'INDIVIDUAL.GARRISON.GARRISONED'

If a worker is gathering from e.g. a farm field and that worker has a pending queued order, it will keep gathering and shuttling back to a dropsite until the resource node is depleted. However, it fails to drop off the last batch of resources it gathered before the resource node depleted, instead beginning working on the queued order immediately, carrying the batch of resources with it.

If a female citizen is queued to garrison a building that is already fully garrisoned and then walk somewhere else, she will walk to the fully garrisoned building, not enter (because it is full) and then proceed to walk somewhere else as ordered.

If a Gaulic Spearman (and probably other units) is queued to do the same thing, he will immediately disregard the garrison command and instead walk somewhere else without walking to the garrisoned building first.

If a female citizen is queued to walk somewhere, then garrison a full building, then walk somewhere else, she will walk to each of those three waypoints.

If a Gaulic Spearman is queued to do the same, he will walk to the first waypoint, the to the second (the full building) and then stop, without ever completing the order to reach the third waypoint.