When using the distributor the behavior of retries and the related message flow is different between major versions.
Immediate Retries are always performed on the worker.
The behavior of Delayed Retries is different between major versions.
Delayed Retries has two configurable items TimeIncrease and NumberOfRetries.
The message will be retried on any available worker. Message processing is not sticky to the worker.
The Delayed Retries policy is applied only on the workers for both TimeIncrease and NumberOfRetries settings. If a Delayed Retries configuration is available on the distributor then these settings are ignored.
When an error occurs the worker schedules the retry according to the SLR TimeIncrease setting and when the corresponding timeout is triggered the message is forwarded to the incoming queue of the distributor which will then forward the message to an available worker.
Due to the behavioral differences between major versions it is advised to have the SecondLevelRetriesConfig exactly the same on both the distributor and the workers even though it could be that settings are ignored.
It is assumed that NumberOfRetries and TimeIncrease are the same on the distributor and the workers.