Hi rthompson,

Please consider that the subscription_timeout_millis setting does not apply in case an explicit unsubscribe request has been received for that item.
It applies only in cases where the unsubscription is implicit, due to the termination of the client session that requested the relevant subscription.
The timeout was meant to address cases like a client just refreshing the page, with a quick re-connection after a disconnection, to save a couple of probably useless unsubscribe and subscribe calls to the Data Adapter.

Regards,
Giuseppe