Finally resolved the oil migration issue on the 2008 KTM 530 EXC, the first year of the XC-4 motor that contained separate motor oil and gearbox oil compartments.
The bike’s factory breathers is a closed system connecting the crankcase from the valve cover, the gearbox, and the air intake after the filter.
Oil migration was happening out of the crank case breather, which is connected to the top of the valve cover. Visible through clear breather tubes, there was oil in the tubes leading to both the intake and gearbox. No telling at what ratio, but enough to require topping off the engine from half, as viewed through the sight glass; equivalent to a few ounces, every few hours.
The kickstarter lever, on the right hand side of the bike, has an idler gear accessible under the clutch basket and located directly under the gearbox breather. It’s a known issue that the oiling holes are found to be misaligned.
Indeed my bike had misaligned oiling holes, and thus rectified the issue by extracting the bearing bushing and reassembling in the correct oiling hole alignment.
Used an appropriately sized socket and hammer to drive the bushing out.