Using a conditional field and saving to the database does not clear values when controller field is unselected

When you save computed values to the database the computed field will still display the values for a conditional field even after you edit and untick the triggering field.

Example

field_center

A1
A2
A3

User selects A1 which brings up field_rack
B1
B2
B3

User selects all three values and saves.

Computed field - Keys
if field_rack = b1,b2,b3 selected output c1,c2,c3

Computed field keys displays c1,c2,c3.

User then goes in to edit and unchecks B1, B2, B3 and A1 and saves. Computed field still displays c1,c2,c3. Not saving to the database obviates the problem.