From what I can gather and my experience with my 5yr old dock some usb3 chipsets in the docks cause timeouts/freezes. I'm replacing mine soon.
FWIW I now have armbian bionic installed on the 2.5" hhd/dock with the spi flashed with ayufans thing for that. No usb3 hangs and ssh works fine for hours. I think it has to do with how armbian handles UAS/usb module blacklisting/loading vs other distro's. Some kind of advanced insight patches I guess. Couldn't get this to work reliably with Arch/Manjaro arm for rock64 so rocklobster is correct in his suggestion which I fought doing for 2 weeks since I like Arch. Learned a lesson there.
FWIW I now have armbian bionic installed on the 2.5" hhd/dock with the spi flashed with ayufans thing for that. No usb3 hangs and ssh works fine for hours. I think it has to do with how armbian handles UAS/usb module blacklisting/loading vs other distro's. Some kind of advanced insight patches I guess. Couldn't get this to work reliably with Arch/Manjaro arm for rock64 so rocklobster is correct in his suggestion which I fought doing for 2 weeks since I like Arch. Learned a lesson there.