Steps to Reproduce
Issue is always reproducible in IE, and sporadically in other browsers:
Open any form containing an HTML text field (for example, a KB article or an email client).
Paste all text from the attached file.
Type some additional text.
Note that the editor takes a while to respond.
There is no known workaround for this issue. To receive notifications when more information is available about this issue, subscribe to this Known Error article by clicking the Subscribe button at the top of the article.
Related Problem: PRB658009