Can't install to an external drive (only happens with this pkg)

[Twig6943]

[sudo] password for twig: 
Looking for matches…
Remotes found with refs similar to ‘com.spotify.Client’:

   1) ‘flathub’ (system)
   2) ‘flathub’ (system (extra))

Which do you want to use (0 to abort)? [0-2]: 2

com.spotify.Client permissions:
    ipc                   network                 pulseaudio       x11       dri       file access [1]
    dbus access [2]       bus ownership [3]       tags [4]

    [1] xdg-music:ro, xdg-pictures:ro
    [2] org.gnome.SessionManager, org.gnome.SettingsDaemon.MediaKeys, org.kde.StatusNotifierWatcher
    [3] org.mpris.MediaPlayer2.spotify
    [4] proprietary


        ID                          Branch         Op         Remote          Download
 1. [/] com.spotify.Client          stable         i          flathub         193,8 MB / 203,4 MB

        ID                          Branch         Op         Remote          Download
 1. [✗] com.spotify.Client          stable         i          flathub         193,8 MB / 203,4 MB

Error: While trying to apply extra data: apply_extra script failed, exit status 256
error: Failed to install com.spotify.Client: While trying to apply extra data: apply_extra script failed, exit status 256
[twig@twig-tobefilledbyoem ~]$ ```

[TingPing]

I'd guess its unsquashfs failing, maybe --verbose shows more?

Can you elaborate on how you have this on another drive?

[Twig6943]

I'd guess its unsquashfs failing, maybe --verbose shows more?

Can you elaborate on how you have this on another drive?

Custom flatpak installation