Yes, I have isolated the problem to a realtek wifi driver. Weird.
Sadly not :'(. Realtek drivers have gone to pot recently, despite well over a decade of stellar driver support. They've put out buggy ethernet and wifi drivers, which have required many updates on Windows, and have gotten unworking crap into release Linux kernels.
Something has definitely changed inside the company. A year ago I would have praised them left and right, figuring the GbE driver problems in Linux were an occasional fluke. But, it's been happening more often on both Windows and Linux, IME.
I haven't gotten BSODs or kernel panics, luckily, but not connecting to a/the network (sometimes not seeing wireless ones), screwing with other devices on the network (needing reboots of other devices/PCs after doing file transfers, FI), disabling the ability to connect or disconnect w/o a reboot...the little USB ones seem to be the worst, but some GbE NICs have problems, too. Sometimes getting the very latest from Realtek's site fixes things, but only sometimes. Maybe it's hardware bugs, I'm not sure--problems seem to follow the device, not the OS--but it's not what I expect from Realtek.