Linux Mint 22, LibreOffice 24.2.6.2 (X86_64)
I find several similar posts - none describe the same problem. Several strange facts: The “error” did not occur the last time the files were updated in July; I have an “identical” file structure for /2024/, based on the /2023/ structure in July, which does not produce the “error”; If I open the same files using LibreOffice 7.6.7.2 (X86_64) using Windows 10, the “error” does not occur; I was running Linux Mint 21.3 in July. I do not suspect the OS, per se, since the /2024/ structure works fine with Mint 22 but know of no other changes, and question why it runs fine using the Windows version. I am relatively new using Linux but have over 50 years computer experience, and this totally beats me. Why only the /2023/ files, and why a change since July?
I have included screen shots which I believe indicate things “should work”, e.g. no file name discrepancies or such.
Unfortunatly your last screenshot doesnt show the folder »above« MyDokuments/… , maybe its NOT »media« ?
Anybody? If this is only happening to me, what am I doing wrong please?!!? Where should I look in settings, or perhaps file properties?
As you are on Mint and Mint is derived from Ubuntu, may it be that you are using the Snap bundle of LibreOffice and not the .deb packaged version? Snap versions may have restricted access to file systems, e.g. not being allowed to read from /media/.
Thank you. I believe I was OK on this since I have found a solution using the LO that is installed. See the next comment.
The spreadsheets in question had links to named ranges in other spreadsheets. All were created by opening .xls sheets and saving them as .ods. When that happens, the named ranges are retained in the cell, but are not “hot”. If any single range linked from another spreadsheet is not updated, the “file not loaded” message will be shown. The even stranger thing is that simply selecting the cells with #NAME?, copying the line from the input area and pasting it back, resolves the link. It was especially tedious in my case, because at times there are circular references because of the number of spreadsheets involved, and they must be resolved in order. (Perhaps sloppy design on my part with those as the project evolved.)
My conclusion is that sometimes LO is a strange beast. 
As are software developers. The “but I didn’t change anything” always annoys me when I hear it. That “identical” data structure from July was not quite “identical”. 
But at my age I have a short memory.