Example Concept: Overlapping ACLs can cause routing issues by creating conflicting rules that affect packet forwarding. When ACLs on different interfaces have overlapping conditions, packets may be dropped or misrouted due to inconsistent rule application. This can lead to asymmetric routing, where return traffic takes a different path than the outgoing traffic, causing issues with stateful inspection or NAT. Properly organizing and documenting ACLs, and using tools like Cisco IOS or Juniper Junos to simulate and test ACL behavior, can help mitigate these issues.