Hello James,
I am sorry about this delay in responding.
As for your query, I was not able to reproduce the issue of "GridConditionalFormat is not refreshing when the underlying datasource is change". I have tried this case in sample and it seems to be working fine. While the underlying datasource gets changed, the conditional format is getting refreshed and applied to the current cell.
I have attached the sample in the below link for your reference.
http://websamples.syncfusion.com/samples/Grid.Windows/F67639/main.htmSample Details :
1. Applies conditional formatting based on the value in the first column.
2. Clicking on the "Update CurrentCell value" button will update the data source directly.
Please look into the sample and modify it if you still finds any issue regarding this. So that we can look in detail and will provide you a better solution.
Thanks,
Meera.