Not patched so maybe patch will resolve however Haven't seen this noted:

Treasure cant be moved from plantations etc in Age of Discovery to capital for supposed VP Pointsa and 200 gold each..

Even saving the Age of discovery as another scenario and
unchecking immobile and moving then to capital, treasure does nothing once arrives..

Makes it an useless unit..

Not a bug

In order to pick up treasure you need to seize it with a land unit. Move a unit to the city the treasure is in, activate the unit and there should be a button, seize treasure. Once you have the treasure the unit carrying it will be indicated in red if you right click on it and with !!! in the unit box in bottom right of the screen.

Hope that helps