I also came here looking for an answer to the "anytime" question for processing buildings, but I eventually figured it out.
For anyone confused in the future, you can trigger a processing building whenever it's time to activate a card you've played from your hand. Just do it before you activate the card or you'll miss your chance. I guess for technical reasons "anytime" is precisely that time and that time only.
For anyone confused in the future, you can trigger a processing building whenever it's time to activate a card you've played from your hand. Just do it before you activate the card or you'll miss your chance. I guess for technical reasons "anytime" is precisely that time and that time only.