I’ve fast-tracked the fix for this now, along with some other small fixes which were pending.
This bug will only have affected new installs, and meant that the relevant part of the config which sets up SSL Stapling wasn’t enabled properly, but old/upgraded installs would have been fine.
This wasn’t picked up because the testing didn’t automatically pick up a new LE cert and force applying it, because the VMs used for testing don’t persist, and we could quickly hit Let’s Encrypt rate limits.
I’ve added a task to improve this, and get a full test working normally with certificates from their staging environment.