vlan fdb reference can't be reset to 0 when del all members

[sempSONiC2]

What I did clear vlan fdb reference when delete all vlan members Why I did it if there are fdb entries on vlan members, vlan will also has fdb reference counter. when delete vlan members and vlan, fdb reference count on vlan can't reset to 0, which cases failure on vlan deletion. How I verified it 1 config vlan and vlan members 2 mac learning 3 delete vlan members and vlan Details if related