This seems like a recurring problem w/in trailhead. I had this problem a month ago with the "Drive Productivity with Salesforce AI" trail (https://trailhead.salesforce.com/content/learn/trails/drive-productivity-with-einstein-ai) it would not show the "Prompt Builder Templates Superbadge Unit" (https://trailhead.salesforce.com/content/learn/superbadges/superbadge_prompt_builder_templates_sbu?trail_id=drive-productivity-with-einstein-ai) unit as completed even though when I navigated to it, it would show as completed.
I am now getting something similar with the "Agentforce: Agent Planning" module in the "Become an Agentblazer Innovator" trail.
Seems like the only thing we can do is open a case (https://help.salesforce.com/s/cases).
