So, it turns out the GVFS and SMB Client that the Ubuntu file manager uses is known to be buggy. I switched to a regular kernel mount and everything behaves properly in either dialect of SMB. I'll log a bug with the Ubuntu team as I found a simple way to replicate it with as single echo command rather than through FreeCAD.
Code: Select all
echo "This is a test" > /run/user/1000/gvfs/smb-share\:server\=diskstation\,share\=fileshare/TestFile.txt
This would create a 0 byte file when speaking SMB2 and the actual file with data when speaking SMB1.
Thanks to all who contributed to this troubleshoot.