Check
Stable responses over HTTPS
Stable responses over HTTPS is check A5 in the fifteen-point audit. The site answers consistently, quickly, and with a valid certificate on every checked URL.
What counts as evidence
Response times, TLS validity and the consistency of repeated requests during the check.
How to fix it
Fix certificate renewal before anything else; move slow renders behind a cache; make sure the site answers the same way twice.
Where this sits
A is the group: accessibility, comprehension, or extractability. The groups run in order — a crawler that cannot reach the page never reaches the reading checks — so fix the earliest failing group first. The full definition of all fifteen items is in the standard.