Postinstall fails trust check for formula from already trusted tap

[szampier]

The postinstall starts, but during the cleanup phase Homebrew reports that the formula is untrusted, even though the containing tap is trusted.

linuxbrew@somehost:~$ brew postinstall eso/pipelines/esopipe-giraf-demo
==> Postinstalling esopipe-giraf-demo
Warning: Sandbox unavailable: running post-install without sandboxing!
==> brew cleanup --prune=all esopipe-giraf-demo
Last 15 lines from /home/linuxbrew/.cache/Homebrew/Logs/esopipe-giraf-demo/post_install.01.brew.log:
2026-08-14 15:32:08 +0000

brew
cleanup
--prune=all
esopipe-giraf-demo

Error: Refusing to load formula eso/pipelines/esopipe-giraf-demo from untrusted tap eso/pipelines.
Run `brew trust --formula eso/pipelines/esopipe-giraf-demo` or `brew trust eso/pipelines` to trust it.
Warning: The post-install step did not complete successfully
You can try again using:
  brew postinstall eso/pipelines/esopipe-giraf-demo
linuxbrew@somehost:~$ brew trust
All official taps and commands are trusted.
Trusted taps:
  eso/pipelines

[p-linnane]

This is a problem with the tap you are using. It runs a nested brew cleanup, which isn't going to work against your trust store.