Figured Bass numbres dissapears when you add notes in a different voice
Attempt to create a template for a 4 part-harmony exercise in two staffs only, with a figured bass .
Create a bass with FB in the voice 2 on the bass staff,
then you add the other voices. When the tenor is added (voice 1 in the lower staff) some FB could dissapear, if there are more than one in a single note in the bass. (See the example)