I would just take a step back and put them into a cementing area again. It sounds like you used a pen for cementing? I would keep them in the pen, and sleep near them so you are close by in case they get into a scuffle.
My two lived together for 2 weeks and then got into a few fights. I think it’s very normal for them to have some scuffles while they re-establish their relationship living together 24/7. You just have to stay strong and keep them together, and be there to separate them in a scuffle if needed. I didn’t get much sleep in those first few weeks, and I spent a lot of time sleeping on the couch, but the more time you can keep them together the faster they will learn to live peacefully together.
And don’t worry – nothing you did set them back or messed up their bond. They’re just trying to figure out how to live together and somehow when you separated them briefly they had an issue when they were put back together. From now, keep them together at all times since you know the brief separation can set them off.