Biting fiercely to step-up, but not otherwise

My GCC Mochi has lately (perhaps for two months or more, I can't remember the last time she stepped up without biting) biting really, really HARD to step up on me. No matter which finger I offer, or at what level, she fiercely attacks my hand to step-up. My SO can offer her finger, and she'll peacefully step up without complaint. But I can only manage to get her to step up if she tries to bite through my finger first. Ouch!

Once she's actually on me, she fine - she doesn't mind being stroked, pet, etc. It's just the act of getting her to step up that triggers her to attack. Clueless...any suggestions or help!?

(to comment after having the read "for no reason" thread further below in the sub-forum) - nothing has appreciably changed, as far as I can tell! Clean cage, check, good food, check, play-mate's presence, check, outside time, check!

Wellllllllllllllllllllllllllll...
Some will say I am the voice of surrender... it's probably true!

I have an old bird who is set in his ways, and may be a good example of what can happen if you DON'T do effective, early intervention.
I have reduced biting to almost zero over the decades... not because I've changed the bird, but I have changed me. And a lot of that has involved giving up on a lot of my desires/expectations. After years of battle, I surrendered. I don't do stuff that gets me bitten. I don't scratch his head much, ever... tail is okay. I NEVER do stuff that makes him mad... I don't touch others when he's out; I rarely try to get him to step up onto my hand first. Hand-held perch first, then hand. In some ways, I swallow my disappointment at having such a little monster for a pet, but he is what he is. I ALWAYS wear my hair down when he's on my shoulder, so all he can bite is hair. Really, I don't involve hands much... he doesn't like them. He seems to think the real ME is my head, perched on a weird moveable tree with questionable appendages.
Since he's fully flighted, the ONLY way I get him into the cage is to toss a chile pepper in and he flaps in after it.
But please... listen to and try all the good advice you'll get here. Don't surrender until you know you've done your best. Then just accept and love whatever/whoever your bird turns out to be.
My darling is kind of a worse-case scenario, but we have it all worked out between the two of us.
Good luck!

My little guy recently started growling, then biting my finger (not hard or breaking the skin) when asking him to step up. I remember reading somewhere to hold a treat up that he would want, but needs to step up to get it. I have been using the treat every time I want him removed from the cage... and it works perfectly. He loves pistachios, but never when he is removed from the stand, chair or floor. They are strange little things to try and understand.

Thanks for the responses. Maybe my finger will callous over the point that I won't feel it as much! I'm going to try just reading her moods better and presenting the hand in a different way.