Microsoft.AspNetCore.Components.E2ETest.ServerExecutionTests.PrerenderingTest.CanRedirectDuringPrerendering failures are connected with the fact that we are not stopping the renderer effectively:
if the stopping occurred in prerendering, it will be valid for prerendering only and in the main rendering, _rendererIsStopped will already be false. We have to find an effective way to communicate the pause between the calls of BeginRenderingComponent.
wrong diagnosis.
We are not stopping effectively because we planned for the whole ongoing batch to finish rendering and the pause was planned to be effective only for future UI updates. We are in the middle of processing the render queue in ProcessRenderQueue

My proposal:
this test has to be changed, in the current situation we are not able to maintain the expectations of not finishing the ongoing render batch. This does not affect the correctness of navigation process.

An alternative (I need your opinion on this, @javiercn):
prevent editing _batchBuilder.ComponentRenderQueue when _isBatchInProgress=true. We can gather the items in a separate, "waiting" queue and move them to the main one in the end of ProcessPendingRender, when we are clearing _isBatchInProgress = false;. This way we will make sure that stopping was done properly.

Using the "waiting" queue is not an answer - it blocks rendering because most of the render items is added when _isBatchInProgress=true. A better solution is to implement a mechanism that will prevent adding new items to the queue after we signaled the stop of rendering.
Changes:
In the previous version, we could not trigger a new queue processing if the signal was sent but we were able to edit the ongoing processing.
In the new version, we cannot edit the queue (== to edit the ongoing processing) if the signal was sent. We had to add the "signal stop render" method to the Renderer API.