Clicking Launch Cairo-Dock on startup causes a Bad file descriptor error

The "Launch Cairo-Dock on startup" feature wasn't working, so I looked into what it does. "Run cairo-dock and right-click the dock and go to Cairo-Dock > Launch Cairo-Dock on startup. The settings will be stored in ~/.config/autostart/ and sourced the next time you login." According to <https://glx-dock.org/ww_page.php?p=First%20Steps&lang=en#4-Cairo-dock%20method>. I tried terminating cairo-dock and then running it from the console. When I click the option to launch on startup, it displays the following:
"warning : (/build/cairo-dock-3.4.1/src/gldit/cairo-dock-file-manager.c:cairo_dock_copy_file:528)
  couldn't write to file '/home/owner/.config/autostart' (Bad file descriptor)"

I ensured that the user has write permissions not only on all files in the directory but also the directory itself.

If I move my ~/.config/autostart directory and try again, I get the same error, though cairo-dock successfully creates the directory. The directory is empty and still contains no shortcut in that case as with the usual case.

The issue is the same whether I start from a graphical terminal or from Alt+F2.

xdg-utils is installed (I'm not sure whether that matters).

- OS: Debian 10 (buster) 64-bit
- compositor: compiz (transparency is working if I load it before cairo-dock)
- desktop environment: lxqt
- cairo-dock version: 3.4.1

Here is content of debug.txt after doing "cairo-dock -l debug > debug.txt" then clicking launch on startup:
https://pastebin.com/KCfGJWRY