ServiceMesh 2.1 will ship with an envoy based on the 1.17 release line (instead of the 1.14 line we have right now). That'll fix a few flakes that we currently have in TestActivatorHAGraceful and TestProbe.

We might have to wait for 1.20 (Knative 0.26) to do that or backport rhn-support-knakayam's work on Envoy v3 API to earlier Kourier versions to make that fly.