Copy and Paste Turns Space on Paragraph on the Editor (Firefox 25.0)

When copying and pasting content inside tables, in Confluence, it behaves different depending on how you insert the text. Here's the steps to reproduce and better understand:

With Shift+Enter together:

1. Edit a page and create a table
2. Enter text separated by lines (using SHIFT+Enter)
3. Copy the text and Paste in other table:
   

With Only Enter

1. Edit a page and create a table
2. Enter the text separated by lines (only using ENTER)
3. Copy the text and paste in other table
   

Screenshot attached for further reference.