Thanks for bringing this to my attention, @ben41.
I'd like to help route you to our Online Support so they can check this further using their extra tools. This way, they can investigate why you're sales transactions' amounts are not showing on the Sales graph.
The transactions recorded (invoices and sales receipts) should ideally show on the dashboard sales for the period specified except for journal entries and bank deposits. Since we don't have any open investigation about this unusual behavior, it'd be best to contact our support so they can isolate this.
You can get real-time help from our chat support. Just click on this link to connect with a QuickBooks expert: https://help.quickbooks.intuit.com/en_AU/contact.
If you have other questions about your sales transactions, you can always get back to me. I'll be around to help.
I'm having the same issue. Only noticed it today as it has been working fine.