I hope you mean 1TB, not 1GB.
Did they finish the vetting process?
You can use Earnings calculator (Update 2022-12-08: v12.3.0 - Now compatible with node version 1.62+ - Detailed earnings info and health status of your node, including vetting progress) to check the vetting progress.
Do they started in the same time?
Do they have neighbours in their /24 subnet of public IPs?
Neighbors
And also - what do you have on Payout Information page for the period since start date?