Apex domain serves 200 instead of 301 despite "Redirects automatically to primary domain"

Site name: agilebizsolutions.netlify.app
Custom domain: www.agilebizsolutions.co.uk
DNS: external (Porkbun)

Problem

My apex domain agilebizsolutions.co.uk is serving the site directly with a 200 response instead of redirecting to the www primary domain. Google has consequently indexed the apex and selected it as canonical, overriding the canonical tag on the page, which declares the www URL.

Configuration

In Production domains, www.agilebizsolutions.co.uk is marked as Primary domain, and agilebizsolutions.co.uk is listed below it with the label “Redirects automatically to primary domain”. Screenshot attached.

DNS at Porkbun is an ALIAS record on the apex pointing to apex-loadbalancer.netlify.com, and a CNAME on www. The apex resolves to 75.2.60.5 and 99.83.231.61.

What I have already tried

I initially added explicit forced 301 redirect rules for the apex in netlify.toml. These had no effect, so I have removed them and redeployed. The current netlify.toml contains only a build block and header blocks, no redirect rules, so nothing custom is interfering.

Evidence

Google Search Console’s live URL test on https://agilebizsolutions.co.uk/ returns “URL is available to Google” and “Page can be indexed”, confirming the apex returns a 200 rather than a redirect. Screenshot attached. This was tested after the most recent deploy.

Question

The dashboard states the apex redirects to the primary domain, but the observed behaviour is a 200. Could you check what is happening at your end, or tell me what else I should be looking at?