When you quote a message that has inserted attachments and then add your own attachments, they appear as if they have been inserted in the initially quoted message.
Steps to reproduce:
- type a message, add an attachment #1 and use the button 'Place inline';
- submit the message and quote it to create the next one;
- add an attachment #2 and submit the message.
Result: the attachment #2 is inserted in the quote.