I have this issue as well. It seems to be a common problem with no explanation. There are several threads on it, heck, I even have a thread about the issue. At first it was with my steeda springs, and gave up with it. Drove on those for several years and was ready for change. I forgot about the passenger rear setting a little higher. I bought some skunk2 springs last year and yep, same corner. I can't even tell you how many times I took them out and manipulated them. I even took a dremel to the rubber donut thingy and nothing fixed it. I gave up again. Just going with coilovers, that should fix it!
Yeah, I's gots me some mods.