[Client] Mac UserKernel process doesn't quit

My Mac's fan was unusually loud today, so I decided to check what was running on Activity Monitor. There were 3 processes with the nondescript name "UserKernel" that were collectively adding an extra 30% CPU util. Only after double-clicking each process and checking the "Open Files and Ports" tab did I see that these were related to LoL. Funny thing is, I actually uninstalled LoL yesterday and the processes were trying to reference nonexisting LoL files in the Trash (which I've emptied). If I hadn't checked, these processes would have been needlessly taxing my computer until (presumably) the next time I restart it.

So to summarize,

1. There's some graceful exit failure with the "UserKernel" process on Macs, possibly related to after an uninstall.
2. "UserKernel" is a very nondescript name; I was afraid this was some other important system process.
3. A google search for "UserKernel mac" reveals all LoL-related issues dating back as far as 2013. I don't know if these are all the same issue as mine, but I haven't seen any response from Riot in most threads.

My specs: OSX on Macbook Pro with Retina. Latest client on patch 6.7. I don't use any overlays/3rd party launchers/etc.