network-manager takes 1-4 restarts in order to recognize and connect to already-configured wifi network, USB dongle NIC

[Alan Tu <8libra@gmail.com>]

Hello, I have a "Debian testing" system installed with Mate. It has
network-manager 1.22.8-1.

My network adapter is an Asus USB dongle based on rtl8814au, I
compiled and installed a kernel module for it and the network works
great, once it gets going.

My problem is, when I boot the system and it gets to the mate login
prompt, the network isn't connected. Then, even after I log in to the
Mate desktop, I'm usually asked for the WPA wifi credentials.

After trial and error, the best fix is for me to get into a terminal
and restart network-manager:
# systemctl restart network-manager

After one to four times of this, eventually network-manager
establishes the network connection.

I think this probably has something to do with network-manager not
recognizing that the USB dongle is plugged in, even though the kernel
module is loaded.

What can I do to troubleshoot this problem, potentially filing a bug?

Or, maybe this is a problem with the kernel module for the USB adapter?

Alan