GitHub App does not show preview results in Pulumi Bot comment when running on self-hosted runner in K8s

[videmsky]

When executing pulumi preview in the context of a PR, the "rich" preview output is not displayed when job is run on a self-hosted runner deployed in k8s via the Actions Runner Controller installed via Helm.

https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/deploying-runner-scale-sets-with-actions-runner-controller

Expected behavior

Current behavior

Preview is correct when viewed in GH Actions job output, but preview is not displayed as a PR comment.

Steps to reproduce

When running a pulumi preview in the context of a PR, I get "rich" preview output when running:
(1) gh hosted runner with ubuntu-latest
(2) self-hosted gh runner on my ARM64 mac

I do not get a "rich" preview when running:
(3) self-hosted gh runner installed with Helm on K8s. (local Kind cluster)

Even in the same PR, I can get the "rich" preview to show with a trivial commit and switching between (1) & (2). Another commit but targeting (3) does not generate the preview.

videmsky/aws-ts-static-website#2

Context (Environment)

Pulumi Preview as a comment is helpful during PR code reviews.

Affected feature

Github App