There's a bug in the RadEditor WordListConverter convert method. See the attached image for details. Note that the variable z is initialized and treated as an array (a stack, actually, with its items being pushed in and popped out). However, perhaps because of a naming scope failure in the js-minifier, the z variable is, under certain conditions, set equal to an HTMLCollection, so a subsequent z.push method call fails.
This sample Word document reproduces the error. It is admittedly full of bad list formatting, because it began life as a PDF, but it does exercise the RadEditor code in a way that causes the problem. Select and copy its content and paste it in the RadEditor demo page here:
Click OK to "clean" the pasted content and note that nothing appears because of the error shown in the attached image.
Verified in the latest Chrome and FF builds on Windows 10.