The article demonstrates how TAR can cause a complete service outage in one zone if pods become unavailable, despite the presence of healthy pods in other zones1
. It also highlights additional limitations of TAR, such as inconsistent behavior with fewer than three pods per zone and potential conflicts with other Kubernetes features like horizontal pod autoscaling

https://buoyant.io/blog/the-trouble-with-topology-aware-routing-sacrificing-reliability-to-avoid-cross-zone-traffic