A photo would be helpful.
I’ve only been doing lacto fermentation of veggies for about a year, and haven’t used a kit, so I’m sure there are people who can offer better suggestions than me. But I’ll offer what help I can. I’ve not run into reddish brown sediment before, but my offhand guesses would be: metals introduced via a utensil or other reactive metal coming into incidental contact with the acidic brine, one of the spices in the pickling brine, metallic impurities in the water you used, or possibly some kind of mold or bacteria.
If it’s just spice gunk, you’re fine. If it’s any of the others, I would consider tossing and starting over after sanitizing everything. The nose is a pretty good poison detector, so if it’s some weird kind of mold or rot, it will be immediately obvious. Pickles should smell like pickles. If they don’t, they are probably bad and not worth risking it.
Regardless, I would not do anything rash until you can post a photo and get more experienced eyes on the problem.