@dinhngtu we couldn't delay any longer and had to deploy the cluster so we swapped the drives with some CD6-R instead. We'll most likely re-explore this later as we have 3 other nodes to deploy soon-ish, and I'll get some logs then.
@pierrebrunet
I'm jumping in here as well. Reporting that the PR fixes it for Google Workspace as well!
However, the checkbox in GW is called "Signed response".
No further adjustments of the plugin itself was needed.