Invited users only see their custom dashboards in the sidebar
This is normal. Creating a custom dashboard adds a new custom dashboard only under your account. Contacts who are invited to view your account will not see your customized versions in their side panel.
If you want to share a custom dashboard view that you created, you can use the Share option.
Sharing with individual people will add the dashboard to their sidebar when logged in to their user account.
You can also create a public sharing link to provide read-only access to the dashboard for anyone on the internet, even those who don’t have a user account.