noindex on an hreflang alternate poisons the whole cluster

noindex on an hreflang alternate poisons the whole cluster

A subtle, high-impact mistake: pointing an hreflang tag at a URL that carries noindex (or is blocked in robots.txt).

The logic. hreflang is a relationship between indexable alternates. If page A lists page B as its German version, but B has a noindex directive, you've created an internal contradiction — "index this as an alternate" versus "don't index this." Google honors the indexing directive and drops B, which then breaks the return-tag chain for every other member that referenced B.

How this arises in practice:

— Staging or thin locale pages shipped with noindex but still wired into the cluster template
— A locale temporarily de-indexed (out of stock, legal hold) without removing it from alternates
— robots.txt disallowing a localized path, so Google can't even read its hreflang to confirm reciprocity

The fix has two valid forms:

— If the locale should rank, remove the noindex and the robots block
— If it genuinely shouldn't be indexed, remove it from all hreflang sets, not just its own — orphan it cleanly rather than leaving dangling references

Nuance: don't "fix" this by adding noindex to silence duplicate-content fears across languages. Translations aren't duplicates. The correct state is fully indexable, self-canonical, mutually referenced. Half-in/half-out is the failure mode — pick fully in or fully out.