Converting Endnotes to Footnotes return blank reference

Hi! 

TL;DR: In some documents, when I try to convert Endnotes to Footnotes with the menu option, my Endnotes return mostly blank. I have the reference number at the correct place, but the reference stays behind, numberless. The same thing happens if I try manualy, reference by reference. What can I do?

Long story: I need to convert my InDesign document into Wordpress after all the editing is done. They all are research paper, so many many references. I want to keep the references linked to save me the hassle to relink them one by one (as they are so many), and it seems to work if I convert my endnotes to footnotes, extract the document to RTF, open as Word and copy/paste the result into Wordpress. However, some documents, and I do not understand why, do not let me easily transfer my endnotes to footnotes. They "convert" the right numer of references, but the result is just numbers being transferred at the end of the correct page but the data stays behind, unlinked to everything. I just updated the software to see if it was corrected with other bugs, but my problem remains.  

Maybe a script? Maybe an easier way to achieve my goal? Maybe something else I can do? Thanks!