FIB Entries not getting removed when router interface deleted

1. Create Network,
2. Create Subnet(IPv4)
3. Create port and boot VM
4. Create Router R1
5. Create Subnet2 (IPv6) with SLAAC Mode
6. Add subnet2 to Router
7. Create port and Boot VM
8. Validate all IPv6 entries observed in FIB

 FIB entries not cleaned.