Why the purchasing documentsare not generated if images are added to negotiation

Summary:

Cannot generate Purchasing Document when adding images to the negotiation in the introduction text section.

Content (please ensure you mask any confidential information):

We have an issue when creating a RFQ negotiation: if images are added to the framed fields in the introduction text section, the purchasing documents for the buyer and the supplier are not generated we have the following error message "The file was not downloaded or was not downloaded correctly."

And once we remove the image the purchasing documents are generated correctly.
Could you please help with that?

Version (include the version you are using, if applicable):