Ryuji saw the original tape, before the copy was made... So he was already cursed before seeing the copy... and yet by Asakawa making the copy and showing it to Ryuji, she was saved... even though Ryuuji was already cursed at that point.
So suppose this happens... two people watch the tape together. They are both cursed... They each make a copy of the tape, and show it to the other person... Are they both saved now?
I think the way it works is that you can only save yourself by showing a copy to someone else.
So she saw the tape first and was cursed.
He saw the same tape after and was also cursed.
Everyone gets cursed, you watch it you get cursed.
Him viewing the copied tape just means she saved herself from the curse and "transferred" it to him, but he was already cursed anyway. Doesn't mean she still can't lift the curse via this method though.
From the wiki:
Desperate to save her son, Reiko realizes that copying the tape and showing it to someone else saved her.
Would've made more sense if Yoichi (the kid) had watched the copy instead of the original, or if Ryuji had seen the copy before the original. Wonder this qualifies as a plot hole.
Thit and thpin!