Pretty annoying achievement. Follow Pleccia Guide on Mokoko seeds 11,12.
TLDR: There's a specific painting in the museum in Pleccia that spawns at 4:44 / 16:44 in game time that lasts for around 3 minutes. Painting is located straight ahead from the entrance on a blank red wall behind the statue of a dude sitting with a leaflet in his hand. Interacting with this painting will teleport you to the un-marked location giving you the achievement and two Mokoko seeds.