OutOfMemoryException during entity operations; function timeouts; slow performance from large serialization; ReadEntityStateAsync returns default(T) if docs followed literally (outdated). Seen in Consumption plan with states >50-100MB.

Azure Durable Functions entities store state in Azure Table Storage (max 1MB/entity, 64KB/property). Larger states auto-move to blobs. However, every operation requires full state deserialization/serialization in function memory, causing OOM on Consumption plan (1.5GB limit) for large states (~100MB+). Outdated docs mention 16KB ReadEntityStateAsync limit (no longer enforced, per GitHub).