I have tried in Hungarian version.
Make a cross reference to an endnote (Insert-> Cross reference-> select Endnote-> select Reference -> select an item).
Save the document as .odt
Reopen the document
The cross reference displays an error. The error message might be different, My latest case said: "Hiba: A hivatkozás forrása nem található"
No problem for me running Bodhi Linux 4.1 Master using EN (USA) locale. Not marking as WFM as I am not testing on Windows or on Hungarian locale but wanted to provide these details.
Sory, I have made an error in procedure. The correct procedure contains:
Save the document as .doc
I can confirm this behaviour with Windows 8 and LO 188.8.131.52.
I saved it as .doc - file.
If I save it as .docx and reopen the file - the reference field is lost but the information of the cross reference is kept.
I think this is really a severe problem because you like to cross reference to endnotes in long documents more often. (at least I do this in my texts.
*** This bug has been marked as a duplicate of bug 42346 ***