Thank you for contacting Syncfusion support.
We have checked your query “NumberDecimalDigits="2" does not working” in Xamarin Forms version 126.96.36.1997036 and SfDataGrid product version 188.8.131.52. We would like to inform you, Issue is not replicated from our end and NumberDecimalDigits in SfDataGrid working fine. For further reference, we have attached the screenshot and tested sample following here.
Xamarin Forms Android :
Xamarin Forms UWP:
If the sample doesn’t meet your requirement, kindly modify the sample based on your scenario and revert us back with replication procedure, it will be helpful for us to give you a better solution.