Thrown when a delivery held on the ingress behaviour-chain gate (PipelinedBroker) waits longer than the configured chainReadyTimeoutMs (default 10 000 ms; 0 waits forever) for the behaviour chain to open.

The gate opens at the end of onInit; a dispatch still held past the bound means onInit never ran to completion — most often a plugin that publishes during its own register() while a behaviour factory is configured, which closes a circular wait (publish → delivery → gate → onInit → the register() that never returns). The gate itself is left in place, so later dispatches refuse the same way rather than delivering through a partial chain.