Thank you for posting in the Community, CAZZY52!

There's no reported product investigation at the moment when it comes to delays in syncing invoices from QuickBooks Time to Xero. It's good to know you were able to contact our Customer Care Team about the unexpected behavior you've encountered. That way one of our experts can further check with our product team to isolate the situation.

In the meantime, have you tried using an incognito (in private) window when trying to import your invoice to Xero?  A private browser does not save any activities, which is why it's a good start to use it for any unexpected behavior in the program.

Here's  how:

• Google Chrome: press Ctrl + Shift + N
• Mozilla Firefox: press Ctrl + Shift + P
• Safari: press Command + Shift + N

If you're able to import the invoices without delay, then go back to your default browser and clear your browser's cache.

Also, you can check the following article to learn more about system requirements and supported browsers: System requirements for QuickBooks Online, Accountant, Payroll, and QuickBooks Self-Employed.

Post again in the Community if you need more help. I'll be around to help you.