Thank you for clarifying this!The "Have 4 of Type A & 4 of Type B Military Unit" quests require that you have no more than 2 of each unit type it asks for before it will show in the recurring quest rotation. So, if you have 3 or more of either unit types, you must delete all your extra units before that quest will appear.
In CA, these Military Unit quests are:
4x Ranger & 4x Musketeer
4x Ranger & 4x Field Gun
4x Dragoon & 4x Grenadier