Pinecone change history: [Serverless][GCP][europe-west4] 5xx errors on read and write operations for some indexes

Pinecone reported a major outage causing 5xx errors on read and write operations for some Serverless indexes in GCP europe-west4. It started at 2025-12-15 10:39 UTC and was resolved at 2025-12-15 22:02 UTC, lasting 11 h 22 min; a fix was implemented, but no cause was stated.