Two components of the det-id bug class were missed in the earlier migration:
NumberCounter's wrapper/counter ids and count-up script, and the shared
form-relay-wiring fid (used by ContactForm/FormContainer). Both used
Math.random() for exported HTML ids, breaking caching/diffing across exports.
Migrate both to scopeId(nodeId, fallbackSeed, prefix), threading nodeId
through NumberCounter.toHtml and relayFormWiring (via ContactForm.toHtml and
FormContainer.toHtml, both now passing nodeId as their 3rd arg).
