I have an issue with handheld sync with MC for Linux (using version 103). Specifically, some files are not syncing, and I think I've narrowed it down to an issue with trailing periods.
I have the sync options setup to place files in directories by [Album Artist]/[Album], and that works fine for 99% of files, but any artist or album that has a trailing period in its name throws an error during sync and does not sync. As examples, the Rolling Stones album "Exile on Main St." will not sync, and neither will any track by the artist "H.I.M.". Interestingly, the sync seems to create the directories successfully, but then errors out before copying any files or additional sub-directories. To follow my examples above, a directory called "Exile on Main St." is created under Rolling Stones, but is empty. Similarly, a directory called "H.I.M." is created but no subdirectories for any albums are created.
This seems to be the case whether I sync to an actual handheld or to some directory on my NAS (which are shared via samba); I get the same results in either case. When I try to sync to the same handheld using the Windows version of JRiver and the same directory rules, the files all sync, and I see them correctly on my device. One key difference though is that when I look at the filesystem, the directories Windows JRiver creates lack the trailing period (i.e. Windows JRiver made a directory called "H.I.M" and "Exile on Main St" and filled them with the appropriate files).
I assume this is some kind of issue with cross platform file naming conventions and/or file system compatibility? I only recently started using the handheld sync function on JRiver for Linux, so I don't know how long this has been an issue. Let me know if I can provide any more info!