Problem with hyperlinks when saving calc as excel

Existing libreoffice spreadsheet with links to files outside the spread sheet. They were all working until I saved and closed the document now none of them work. However when I made a change in format from file:///studies/adc.doc to file:/home/keil70/Desktop/studies/adc.doc they open. Another problem is when I save file in the xlsx format all links revert back to original format. Also the edit "links’ is grayed out in all cases and when file is saved and reopened it appears it does not recognize any hyperlinks as I do not get a request to update.
Added info, when I ctrl click on the link as formated I get this message /studies/adc.doc does not exist but when I edit and add all the folder names it will open. I have over 50 links on my spread sheet that were working and hoping to not have to edit each one.
Sorry for the long question. I am running Linux mint and Libreoffice 5.1.6.2
ketl70
Edit - I just noticed that even when file saved as .ods the links reverted back to file:///studies/ which do not work. Thanks.

Is there any sensitive data in those documents? If not, could you share them here publicly so more experienced users can take a look. Maybe you can make a new, dummy documents showing the problem?

There is a reported bug tdf#76047 about broken links saving as xlsx, as I have seen the issue seems happen with link entered as array.

Here is my answer, As long as the file was saved in Libreoffice all links remained active and worked as expected. Problem occurred when saving as xlsx file type. Reason is unknown but above comment suggests a bug tdf#76047. I will consider this question closed.