On the craft and construction page, when you have increased your building to the next level, the level below it becomes constructable again.  I have been afraid to see if it actually works and downgrades the building.  Is there some way to lock building recipes lower than the current grade on your buildings without affecting the ones you need to build several of like the statue recipe or climbing gear?  Thanks.

Thanks for reporting!

The logic is updated to check for the higher level buildings.

Sorry for the inconvenience.