It could be a file permissions (specifically, lack of write permission) issue. First let us see if the path is correctly being changed.
1) Download and install the Journal Text Sledgehammer addin (link immediately below this point), open your journal, and run the addin. Make sure the journal of interest is selected with the radio button(s). If you have opened the journal after running the Sledgehammer, press the "refresh list" button, then select your journal.
https://marketplace.jmp.com/appdetails/Journal+Text+Sledgehammer
2) Navigate to the "Utilities" tab and press the "Scripts into table" button.
3) Press the "Unify paths" button, select "Use local references" and click OK.

4) Press the "Scripts into table" button again.
5) Compare the 2 entries in the data tables created in steps 2) and 4) above. How did (or did not) the path change? Also, you can opt for the "pick a folder" or "enter manually" options in step 3, to see what happens to the path. If the path is being detected and changed correctly (it was, for me), the issue is likely to be related to file access permissions.
Cheers,
Brady