I have a 2012 990 SMT. It has WP 4860 front forks. I've owned it brand new. It's done about 47000km (seasonal/weekend rider - only ridden it in winter). I keep this bike well maintained and clean, but I ride it pretty hard. Road surfaced here is not good. I noticed the last week the stanchions have lateral wear markings. The closer to the outer tube, the worse it is. This wear is not uniform around the stanchion:

The photo does not show wear clearly. Here is a pictorial to describe the wear locations on the stanchion:

Last March, I took my bike to a local performance suspension specialist for an oil and seals replacement. They are highly regarded and recommended among the local community. Long story short: they did a poor job and the technician that serviced my forks in my opinion was incompetent or inexperienced. One of the issues is they had mixed up the parts when reassembling my forks. He paired the left stanchion with the right outer tube and the right stanchion with the left outer tube (ie: my vent holes are now located under my bars). Before I took my bike to the specialist, the stanchions were perfect (no wear marks) and for 7 years this was the case. When I owned my 2006 990 SD for 6 years (65000km on the clock), I never saw these marks. My previous bike before that (a 2001 GSXR1000) owned for 5 years (80000km). Again never saw wear marks like these. I keep my forks religiously clean. So seeing this wear is news to me.
My question is, what could be causing this wear ?
I would not regard the wear as something I immediately need to fix, but I will monitor. Apart from when serviced GSX250 forks 20 years ago, I have never touched forks hence and regard myself now with no experience in fork repair/servicing.
Any help/tips/prognosis greatly appreciated