Recommendations for DR Configuration between On-Prem AZs

Recommendation for Virtual Networks
• Recovery plans do not support overlapping subnets in a network-mapping configuration. Do not create virtual networks that have the same name or overlapping IP address ranges.

Quotes from Nutanix Disaster Recovery Guide

I would like to clarify the meaning of the recommendation point (Recovery plans do not support overlapping subnets. / Do not create networks that have the same name or overlapping IP address ranges.). 

Kindly, provide a simple example for clarification, if necessary.