We've encountered similar issues before and at that time this seemed to be related to the fact that the Telerik assemblies were loaded by a class library registered for COM interop which caused a permission issue of some sort. We haven't been able to isolate this on our end in order to troubleshoot it and try to come up with a solution. So far, the only workaround we've found is to explicitly load all assemblies, i.e.
If possible, please send us a simple sample that reproduces the problem, so we can further look into its cause.
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