This report IS NOT about being unable to use /locate on those three structures, but being unable to use them in minecraft:location criteria for datapacks. If needed, those will be separeted into three different tickets.
We're unable to use minecraft:location trigger on (overworld )fossil, simple_dungeon and desert_well. In datapack below I included 2 advancements, 1 that will be unlocked after entering the world (due to this bug) and the second one, that requires visiting all of the structures will already have 3/21.
This isn't about them not being count after visiting, but them being count WITHOUT visiting