A health sweep of every argument-free CI check on main found two red results that were really one fault. A wall-framing post carried the tag decks while three sibling posts used deck. check_post_frontmatter.py refuses a tag spelled two ways, because a split tag makes two tag pages where a reader expects one, and promptctl validate reuses the same check.
The fix was dropping an s from the tag. The more useful fact is that the check already runs in both the Portfolio Pages and Portfolio validate workflows, yet the post merged. When runners are starved, a PR can merge on the checks that did run, so a sweep like platform/ci/main_health.py is the backstop that finds what slipped through. After the fix, all 30 checks pass.