I think that's by design. Renshuu will not show the kanji with lower levels of mastery in quizzes. Once sufficient mastery is present for the kanji & word, it'll be displayed, I believe.
If you still want to force it to show them, I think there's an option in the schedule-specific settings to do that. However, it's better to run Renshuu without it for word mastery.
It's not a level of mastery - it's whether you know it or not.
So those kanji will appear as soon as you study them in a kanji quiz. OR, you can go to Tools > Kanji Index in the menu, then select N3, and mark them all as known :)
It's amusing to see someone complain about this, when it's one of my favorite features of renshuu. The gradual removal of furigana and swapping with actual kanji once I learn them really helps cement the kanji and readings in my memory. Trying to study them in other methods never gets it to stick. But this works really well for me.
It continues to amaze me to hear about and see everyone's different learning preferences, and how renshuu (usually) has a way to match up with those. I always have a few ideas in my head about usage when I design something new, so it's great when I hear that people are using it in that way plus a dozen other ways.
It's amusing to see someone complain about this, when it's one of my favorite features of renshuu. The gradual removal of furigana and swapping with actual kanji once I learn them really helps cement the kanji and readings in my memory. Trying to study them in other methods never gets it to stick. But this works really well for me.
I also enjoy the removal of the furigana because it allows my brain to automatically read the kanji without a little "hint" floating above the words. I realized that I can learn new words quickly if I'm already familiar with the common pronunciations of one kanji. For example, I already knew the common pronunciations of 水 when I learned 水曜日, so I could make an educated guess that it would be すいようび (or みずようび... In another universe.) I honestly crammed all the N5 kanji ASAP so I could remove the furigana and learn the readings organically, but this isn't for everyone.
