Hi stevans,
I am actually not aware of any changes that were made when the new version of the description editor was released that would account for the behavior change you described.
The editor is configured to strip the formatting code from when content is pasted in which contains proprietary Microsoft formatting code (such as descriptions that were formatted using Microsoft Word), but the previous version of the editor did this as well.
As a test, I also copied the description text from one of your active eBay listings and pasted it into the new description editor through Internet Explorer 11.0, and the formatting that was present in the active listings was retained through the entire process.
If you continue to encounter difficulties of this nature, please contact our Customer Support team directly from the “Help” page within your account and we will be happy to continue working with you on this.
Be sure to include the details of where you are copying the text in question from as well in case the issue is specific to using a specific source.
-Mike