Special characters question mark ? \ < > * etc are problematic in smb samba share and I try to get rid of them. In the meantime it's frustrating, but a workaround is to manually map these "invalid" characters to other characters.
I use FreeNAS-11.3-U1 and SMB/Samba with MacOS Catalina and have found that my temporary solution to the character problem is:
Goto Sharing>SMB>Edit
1. Choose "advanced mode" and choose "VFS objects". Checkmark "catia"
2. in the auxiliary parameters paste in the following:
catia:mappings = 0x22:0xa8,0x2a:0xa4,0x2f:0xa5,0x3a:0xf7,0x3c:0xab,0x3e:0xbb,0x3f:0xbf,0x5c:0xff,0x7c:0xa6