So fun fact: Samba shares do not support the question mark as a part of the file name. Also, fun fact: ext4 does. Also, fun fact: when copying large amounts of files in KDE plasma, clicking "yes to all" may conceal the fact that some of these files are not copied. Also, fun fact: blkdiscard is effective.
Legit fun fact though: the NTFS file system does support ? as a part of the file name.