Hi Bert,
Thank you very much for your interest in Syncfusion products.
We are not able to reproduce the issue at our side. We have created the sample and tested with the assembly version 8.2.0.18 (2.0 .Net framework). Could you please modify the posted sample to reproduce the issue and revert us back the same, which helps us to further investigation on this.
Sample:
http://help.syncfusion.com/samples/xlsio.windows/supports/WebFileAccess.zipPlease let us know if you have any queries.
Regards,
Sathish