Issue:

When we try to add more then 2 attachments in a Jira issue comment, only 2 attachments are getting added. No error message but rest of the attachments are not getting added. Tried copy/paste but it haas same results.

Please allow to add more then 2 attachments in one go.

Workaround: 

You can add more attachments to the same comment if you try to add them in group of 2-3 attachments at once. Please try below steps as they worked for me.

1. Click on picture icon from the menu for comments editor.
2. Select 2 attachments and click on Open.
3. Once both the attachment starts showing their preview in comments, hit enter (for new line)
4. Click on the picture icon again and select next set of attachments 
5. Repeat above 2 steps until all attachments are added.
6. Once you are done with adding all attachments, click on save.