Can't upgrade unit in Civ5

[cluckinghen]

Hi, I'm new to playing this game but I can't seem to upgrade any of my Ship of the Line units to Battleship units. I meet all the requirements but I don't see an upgrade button.

A unit can upgrade to a new unit type when the following conditions hold:

the new unit type is an allowed upgrade for the unit
the civilization has the technology allowing the new unit type
the civilization has enough money in its treasury to afford the upgrade cost (see below)
the unit has not expended all of its movement points that turn
the unit is within its own cultural boundaries
the city (of its civ) that the unit is nearest to has access to any strategic resources necessary to build the new unit type


Screenshot:

Spoiler :

Moderator Action: Moved to bug reports and added a spoiler.

 

[Petek]

Can confirm that Ships of the Line can't be upgraded to Battleships, even though all the requirements seems to be met. No mods are in use. Oil is present. Battleships can be constructed in English cities. Even if funds are lacking, the upgrade button still should be present but grayed out. Note that the save file is from Vanilla Civ5, not G&K.

 

[rumleech]

It's because the SoL upgrades to Destroyer rather than the Battleship, I'm afraid.

 

[Petek]

It's because the SoL upgrades to Destroyer rather than the Battleship, I'm afraid.

Thanks for the correction. I was afraid that I was missing something simple like that. It's confusing (to me, at least) because I have the G&K expansion. When I load the OP's save game I get the G&K Civilopedia. In G&K, the Civilopedia shows that the SoL upgrades to a Battleship. To get the Vanilla Civilopedia, you have to disable G&K from the DLC menu before loading the save game. It seems to me that there still is a bug here: The correct Civilopedia should be displayed when you load a save game.

@cluckinghen -- Out of curiosity, what does your Civilopedia show for the upgrade of the SoL?