I assume you cycled the fork as you were adding oil? Made sure no spacers are missing? The damper assembly itself is not really serviceable and nothing but oil should be able to get in and out. Assuming you followed the manual and added the correct amount of oil etc, i can't think of much...
Yes I was pumping the damper rod while I was filling it. I'm pretty sure I have all the spacers because they match what's listed in Mark's service book. The BMW DVD shows a plethora of different spacers on their diagrams. It's a bit confusing but I think they're like that because of the different configurations such as with/without ESA and low suspension. Mark's book shows what appears to be the same setup that I have. Only thing I can think of at this point is that I have an air pocket somewhere it's not supposed to be or the spacers are not the right ones.
I first noticed a symptom of the problem a couple months ago when I took off my front wheel. The axle was extremely tight but I didn't think much of it. The bike did pull to the right which make sense now because the right fork leg was shorter. I've had the 18,000 mile service which includes fork oil done at my old BMW dealer which should be the only other time the forks have been opened besides myself. It could be possible that the parts that are in the fork are not what's supposed to be inside it. Maybe they broke something and swapped the part with a spacer from a different trim? There are 3 different part numbers for the set compression spring on Real OEM
https://www.realoem.com/bmw/enUS/showparts?id=0D13-USA-07-2016-K49-BMW-S_1000_XR_0D03,_0D13_&diagId=31_1215. They did mess up installing the valve cover gasket on that service on that job so I'm not ruling it out (not fun seeing an oil leak straight from the dealer).
I'm going to throw in the towel on this one and take the fork to my current dealer. They're good people and I just want to get my bike up and running. I don't want to keep chasing my tail on something that should be simple. I feel like there's something stupid that I'm overlooking or I do not have the correct parts in the fork. Thanks for the help Antares. I'll post an update after I get my fork back.