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, 29 October 2014
Following this: viewtopic.php?f=59&t=110475
What about Goju Saido? If I invested him the first time, and I bring him back later with Blood of the Preserver xp, he still costs 15G... but does he produce a new Melee 5 attack?
Also, what happens to his GC and Melee Attack if I try to Recruit him from my province (the first time) and I choose to Invest, but he doesn't enter play? (example 1: I don't have enough gold, example 2: he became Reserve and the Battle Recruit action is negated by The Sun Returns)
Goju Saido Invest 10: Melee 5 Attack (this cannot be Interrupted) that may target a card in a player's home (if otherwise legal).
Ben Higgins (rules official), 11 November 2014
Following this: viewtopic.php?f=59&t=110475
What about Goju Saido? If I invested him the first time, and I bring him back later with Blood of the Preserver xp, he still costs 15G... but does he produce a new Melee 5 attack?
Also, what happens to his GC and Melee Attack if I try to Recruit him from my province (the first time) and I choose to Invest, but he doesn't enter play? (example 1: I don't have enough gold, example 2: he became Reserve and the Battle Recruit action is negated by The Sun Returns)
Goju Saido Invest 10: Melee 5 Attack (this cannot be Interrupted) that may target a card in a player's home (if otherwise legal).
Each Invest is a seperate triggered trait, that looks to see if the Invest cost was played the most recent time this card a) entered play for Personalities/Followers/Holdings, or b) was played for it's ability for Strategies.
If you Invested a Goju Saido, then that card was destroyed, then subsequently recruited again (without becoming face down and out of play), it's current Gold Cost would be 15, and if you wanted to get the Melee 5 Attack again, you'd have to Invest again, raising the Gold Cost of Saido to 25.
As for your second question, if for some reason an Invested Personality fails to enter play, the Invest increase of his GC has already happened, so assuming he doesn't go face down and out of play, he will remain at his higher Gold Cost, but you will not get the Invest effect.