I am just guessing here, but I suspect that you added the salts with a profile which was not set for full volume BIAB and then changed the mash profile to be full volume BIAB. When you make this change, the program does not change the materials which have already been added to the recipe, thus you still have the sparge salts added, but they contribute no ions to the water profile, since there is no water being added for the sparge.
When I erased the salt additions and used the water profile to add them again, they came in as mash additions with no sparge additions.
I was able to reproduce your result by changing to a standard mash profile with batch sparge, adding the mineral salts using the water tab, and then changing the mash profile back to the BIAB mash profile.