Except ofcourse that if Sorilea truly is a DF, then she would most likely have been carefull to keep one eye on Cadsuane while closing the door specifically to see and memorize the weaves for Shaidar Haran. I mean thats what spies do. Your idea that a DF infiltrator that has managed to remain hidden for so long would be so stupid as to completely turn her back on Cadsuane while Cadsuane was unweaving her traps simply to properly see the door is what I think is stretching credulity.

So if Sorilea is a DF, the fact that she closed the door is not sufficient proof that she did not see the weaves. If Sorilea is not a DF, it makes no difference because she would not have told the weaves to anyone anyway.