Thank you for the detailed information and for the sample prepared, where I was able to observe the error discussed.
This should be considered a bug in the Spreadsheet functionality. Here you could find the GitHub item
, where you could track the bug status.
As a small token of gratitude, I have updated your Telerik points.
As a workaround for the discussed, you could use the id option
instead and attach manually the required attribute using the render
Spreadsheet event. Here you could find a Dojo sample
, implementing the above suggestion.