Current behavior: The quest to gift a CS a specific unit expires when the unit becomes obsolete (can no longer be trained), unless the player still has units of that type on the map.
Problem 1: The units the player has on the map might not have enough XP to be eligible for the quest. Or they may have a lot of XP and the player doesn't want to give them away. The player shouldn't have to upgrade the units to make the quest expire. Also, this behavior looks like a bug, even though it's not.
Problem 2: It might happen that the quest expires while an eligible unit is traveling to the city-state. That's annoying and forces the player to always check their tech progress before sending a unit (which the AI doesn't do by the way).
Proposal: New expiry conditions: The quest expires if the unit is obsolete and no unit gift is currently on its way to the city-state.
Problem 1: The units the player has on the map might not have enough XP to be eligible for the quest. Or they may have a lot of XP and the player doesn't want to give them away. The player shouldn't have to upgrade the units to make the quest expire. Also, this behavior looks like a bug, even though it's not.
Problem 2: It might happen that the quest expires while an eligible unit is traveling to the city-state. That's annoying and forces the player to always check their tech progress before sending a unit (which the AI doesn't do by the way).
Proposal: New expiry conditions: The quest expires if the unit is obsolete and no unit gift is currently on its way to the city-state.
