A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
A player, 3 March 2014
Myuken Force 3/Chi2 HR-/GC4/PH1 Keywords: Actor • Ronin • Soul of Kyogen Open: Myuken copies one keyword from your target Personality.
If Myuken copy the keyword shugenja, after that, I attached a spell to him. ¿ When begin the opponent's turn the spell must be unattached as Myuken isn't shugenja in this moment?
If Myuken copy the keyword Kensai, after that, I attached two weapons to him. ¿When begin the opponent's turn the second weapon must be unattached as Myuken isn't kensai in this moment?
Regards,
Jon Palmer (rules official), 3 March 2014
Myuken Force 3/Chi2 HR-/GC4/PH1 Keywords: Actor • Ronin • Soul of Kyogen Open: Myuken copies one keyword from your target Personality.
If Myuken copy the keyword shugenja, after that, I attached a spell to him. ¿ When begin the opponent's turn the spell must be unattached as Myuken isn't shugenja in this moment?
If Myuken copy the keyword Kensai, after that, I attached two weapons to him. ¿When begin the opponent's turn the second weapon must be unattached as Myuken isn't kensai in this moment?
Regards,
In both cases, as long as the attachment was legal when you made it, the card will stay attached. However, there's an additional caveat to spells, in that they can only be used by shugenja, so Myuken will need to copy the keyword again if he wishes to use it.