Bionic has changed how it handles "absent" data. In the media plan, when you create a new placement, the quantity and rate fields have no values and therefore will be blank, instead of 0.
For instances where a quantity or rate field is populated and that data is then deleted, the field will become blank.
For instances where a 0 value needs to be represented, entering 0 will change the value from blank to 0.
Calculated fields will display 0 or - accordingly based on whether a 0 or blank is used in the rate or quantity used to calculate them.