Skill assignment via route to agent queue event within voice queue is not being followed for Callbacks.

Scenario:
Voice queue is configured with 2 route to agent queue events. Queue event 1 is set to route to agents with a "Tier 1" skill for 5 minutes. Queue event 1 also has DTMF enabled that allows for callback to be selected. Queue event 2 is another route to agent queue event, but it is configured to route calls to the "Tier 2" skill.

Issue:
Skill assignment is not being followed for callbacks. If a caller selects DTMF option to leave a callback request while in route to agent queue event 1 (Tier 1 skill) the callback is being sent to agents in the queue who are skilled for "Tier 2" calls within the queue.

Expected behavior:
Callback requests left while under the first queue event (tier 1 skill routing) would be routed to the next available Tier 1 skilled agent in the queue.

Actual behavior:
Callback requests left while under the first route to agent queue event (Tier 1 skill routing) are being delivered to agents skilled with the "Tier 2" skill.

Request:
Implement system design that retains and honors skill assignment through out the entire contact life, including callback.