Hi Rosemend,
Thank you for using Syncfusion Products.
We have analyzed your query and we tried to replicate the issue but we are unable to reproduce the issue from our side. This issue usually occurs when there is a mismatch of Xamarin NuGet packages between your sample and SfDataGrid assemblies. Our 14.1.0.41 version of release supports Xamarin NuGet of version 2.1.
Xamarin recommends the NuGet packages to be inline in order to avoid potential issues. So please uninstall all the other version of NuGets and use 2.1 version in the pcl and the renderer projects. Also ensure no other version of Xamarin NuGets were installed in any of your pcl and renderer projects. Ensure to clean and rebuild the project before running it. You can see the software requirements of Syncfusion controls from our read me information.
ReadMe link: https://s3.amazonaws.com/files2.syncfusion.com/Installs/v14.1.0.41/ReadMe/Xamarin_Forms.html
We have created a sample based on your codes in which we got the sample running without any problem. We have attached the sample for your reference and you can download the same from the below link:
Sample link: http://www.syncfusion.com/downloads/support/forum/123668/ze/DataGridSample1501364512
Regards,
Harikrishnan