Treasure map not generated in ship wrecks and ocean ruines

Just started a new world in 21w40a and after visiting a couple of ship wrecks I came to the conclusion that there are no treasure maps generated, instead of that I got a couple of empty maps.

Before opening the chest where the treasure map should be located there is a huge lag spike, it takes a second to open the chest all the other chests opens like it should.

The same is for ocean ruines.

Seed used 8256186221020543252