VIPs not showing in VIP folder in Mail

I’ve had this issue for ages. I have set some key contacts, including my wife, as VIPs.

Only my wife’s most recent 3 emails appear in the VIP folder, none of the other VIPs.

When I search for an email from a VIP, it has the little gold star next to it, but doesn’t appear in the folder.

Has anybody else had this issue? Did you resolve it?