Thank you for reporting this.
I can confirm that this is an issue with the current version of Kendo UI Export.
I created an issue in our GitHub repository and forwarded it to our developers for fixing. You can track its progress at:
Currently, there is no workaround available, if one is present it will be added in the GitHub issue.
Additionally, I updated your Telerik points for bringing this to our attention.
Telerik by Progress