Clutch issue

[KsGman]

Our on a ride last Saturday on my 2011 300 EC, and noticed with the bike OFF and IN GEAR, I couldn't pull the clutch and roll the bike. The clutch seems to be disengaging with the lever while riding.

I noticed that the site glass shows the fluid level down about halfway.

So first, I figured I'd back-bleed with fresh mineral oil (not knowing what the previous owner used) and top off the reservoir. Are you guys using Magura Blood or what is the fluid of choice around here?

2nd-is this potentially a sign that the slave is failing? This appears to be a similar part to hydraulic clutches on other bikes. Is there a cross reference for a re-build kit?

Thanks for the help fellas.
GW