Build Your First Sales Coach challenge fails to detect Opportunity Coaching subagent

I am working on the Trailhead project:

Build Your First Sales Coach

Configure and Activate Your Sales Coaching Agent

The challenge validation fails with the following error:

[Sales Coach Agent] does not contain

[Agentforce Sales Coach: Opportunity Coaching].

Current configuration:

- Sales Coach Agent is Active

- Developer Name: Sales_Coach_Agent

- Locale: English (United States)

- Language: English

- Topic Selector subagent exists

- OpportunityCoaching subagent exists

- NegotiationRolePlay subagent exists

- ProposalRolePlay subagent exists

OpportunityCoaching contains all four standard feedback actions:

- Give Feedback on Qualification Stage

- Give Feedback on Needs Analysis Stage

- Give Feedback on Negotiation/Review Stage

- Give Feedback on Proposal Stage

The current Agentforce Builder uses Subagents instead of Topics.

The validator still reports:

"[Sales Coach Agent] does not contain [Agentforce Sales Coach: Opportunity Coaching] topic."

Has anyone encountered this recently? Is this a known validator issue or is there an additional configuration required in the current Agentforce Builder UI?

Thank you.