Reproduction

1. Create a page with multiple lines of content and save it
2.  Create a second page
   1. add a line of text
   2. on the same line add a display / include macro with the reference pointing to the first page
   3. The multiline content is displayed
   4. Save the page
   5. Re-edit it, no need to change anything
   6. Save it
   7. Multiline content is doubled

The more you loop on step 5 to 7, the more duplicate content you get.

The content seems to be copied into the current document, instead of being kept inside the macro (can be seen by editing in wiki mode)

Expected result

No duplicate content