xdg-open is blocking the terminal on Sway

I'm running xdg-open on Sway (Wayland window manager), and any file that I try to open leads to the corresponding program outputting debug information on the terminal, as well as blocking the terminal till the application is closed. Closing the terminal also closes the application.

Version:

• xdg-utils: 1.1.3+18+g0547886c-1
• sway: r6058.08b3eaf9-1

Observed behavior

• Dolphin (KDE file manager), with firejail sandbox, outputs

Reading profile /etc/firejail/dolphin.profile
Reading profile /etc/firejail/globals.local
Reading profile /etc/firejail/disable-common.inc
Reading profile /etc/firejail/disable-devel.inc
Reading profile /etc/firejail/disable-interpreters.inc
Reading profile /etc/firejail/disable-passwdmgr.inc
Switching to pid 2788, the first child process inside the sandbox
Error: invalid X11 display range
Child process initialized in 10.89 ms
"Existing file /home/ericonr/.cache/ksycoca5_en_b62KZ23RSNqKuiT1nc9EsYyhyFI= is not writable"

• KiCAD, without firejail doesn't output anything but it still locks the prompt and is closed if I close the terminal.

• xdg-open https://google.com tries to start a new Firefox instance, instead of sending the link to the currently running instance.

• LibreOffice doesn't work either.

Expected behavior

An application that's started due to xdg-open should be independent from the terminal that spawned it, so it shouldn't be closed when that terminal closes, nor should it output stderr or stdout to the terminal.

Thanks for any help!