Several months back we adopted Dusty, a 3 yr old, and bonded her with Chilly, another 3 yr old. The bond was successful. We moved into a new house and set them up in a completely neutral space. Over the past 3 months Chilly and Dusty ate dinners together, slept in the same cage, and played with toys together. Today, it's completely different.

Chilly is my travelling bunny. I take her to visit with local kids and elder folks. I can understand that Chilly might have picked up a scent. What do I wash her with?

In the meantime, how do I rebond these two? They still remember their tricks that they do together, but can't remember each other. It's pretty sad. It's like a light switch went off in their heads. Now, they want to constantly fight each other. How can they go from best buddies to tuffs of fur flying!

What exactly is happening? You mention tufts of fur, can you describe the interactions, how they start, progress and how you intervene.
If their break is due to frequent absence of your travelling bun, why don't you take the other bunny along on those trips? Trips together will fix this.

I take Chilly out with me for a few hours during the week. Most of the time (before this started happening) they're together in the same cage when I'm not home and they free roam when I am. I don't travel with Dusty because she doesn't like being handled or travel well unlike Chilly who's been handled since she was a baby. Do you think car rides together would re-bond these two??

At home, what's been happening is Chilly would charge at Dusty and vice versa when they're free roam. I've set up 2 cages now for evenings and unmonitored time. When it comes to dinner time they used to eat out of the same bowl, but now they just want to box each other and the food bowl gets knocked over. Last night I put them side by side, petted them and talked to them hoping things would change. Chilly squirmed out of my holding her and nipped Dusty on the thigh. Dusty, on the other hand, seems to be clucking/grunting a lot more than usual.

This morning I set out the pellet food bowl and let Dusty out. She ate. Then I let Chilly out. They started to box again. So I plucked Chilly out of the mix and again, fur everywhere. Dusty got a time out. What's interesting tho is that I caught Chilly and Dusty starring at each other through the cage, like they were talking. Could they have gotten into a tacit disagreement?

It's amazing how quickly these two seem to have forgotten that they used to groom each other and play together. Both buns are fixed, if that matters any. Any insights to these two would be greatly appreciated. Thanks!

They must travel together if you rebond them and want them to stay bonded. Dusty may get used to travelling and you wouldn't necessarily have to handle her much. She could just be a travel companion for Chilly. I would take the two for travelling together, on car rides now, to rebond them and only hold meetings between them in a neutral area. Once they stop the boxing you can try feeding them together again. Try putting them on your lap together and petting them, it may help to reduce their aggression, too.