Seems I found a workaround.
I've not been deep too far but mainly what I found is that GoZPublicPath/GoZBrush/GoZBrushFromApp modifies the ma file (especially when the ma file is small). The bug has been introduced in the 4R4, in some way, probably because of the small changes done to the maya ascii file format by the 2013 version.
So I went to this simple idea: unlock and lock the file before GoZBrushFromApp accesses it.
In the GoZBrushFromMaya.mel (usually located in C:\Users\Public\Pixologic\GoZApps\Maya\)
@ line 488 change this part of the code for
It's python so it should work on any os.
// Then exports it to a Maya file. $maFileName = $GoZProjectPath + $gozName + ".ma";
python ("import os, stat\nmaFile = '" + $maFileName + "'\nos.chmod(maFile, stat.S_IWRITE)");
sysFile -delete $maFileName;
file -f -op "v=0;" -typ "mayaAscii" -es $maFileName;
python ("import os, stat\nmaFile = '" + $maFileName + "'\nos.chmod(maFile, stat.S_IREAD)");