It appears you are not alone and that unfortunately this is a kernel issue that appears to have started since Linux kernel 5.1. Here's a bug report I found about frequent disconnects for your 8260: https://bugzilla.kernel.org/show_bug.cgi?id=203709
I cannot guarantee that an LTS kernel will fully work on your system, but you are welcome to try should you desire. It appears you're on the
nvidia-glx-driver for current, so I'd try the following our Installing an Alternative Kernel documentation. Your command should look something like the following (which is not necessarily comprehensive, since I don't have a full list of what additional modules / packages you might have installed related to the kernel):
sudo eopkg install linux-lts nvidia-glx-driver virtualbox-guest
After that, you will need to likely spam the spacebar after a reboot to get the boot menu to come up (if you're under UEFI) and choose the LTS kernel (4.9.188-135). If that works for you, you can run
sudo clr-boot-manager update and the LTS version should be the default. If it doesn't, you may need to re-install the "current" modules, shown in the table in the doc I linked.
Thanks @Justin for getting the commands to provide the details, and to @crom5 for providing them 🙂