unable to configure new skill "spotify"

[junefish]

I just installed Almond from flatpak.

Steps to reproduce

1. Menu > My Skills > Configure New Skill
2. double-click on Spotify

Expected result

Spotify gets added to the skill list

Actual result

Error popup:

Sorry, that did not work:
GDBus.Error:org.freedesktop.DBus.Error.Failed: Invalid
parameter use_pkce for mixin org.thingpedia.config.oauth2

Other skills, like Weather, XKCD, The Cat API do not produce this error.

My flatpak version is 1.12.7 and all flatpaks are up to date, although running flatpak update after installing Almond (did not happen immediately before installing Almond) gives the following output:

$ flatpak update
Looking for updates…
Info: org.gnome.Platform//3.36 is end-of-life, with reason:
   The GNOME 3.36 runtime is no longer supported as of February 13, 2021. Please ask your application developer to migrate to a supported platform.
Applications using this runtime:
   codes.nora.gDiceRoller
Info: org.freedesktop.Platform.VAAPI.Intel//19.08 is end-of-life, with reason:
   The Freedesktop SDK 19.08 runtime is no longer supported as of September 1, 2021. Please ask your application developer to migrate to a supported version
Info: org.freedesktop.Platform.GL.default//19.08 is end-of-life, with reason:
   The Freedesktop SDK 19.08 runtime is no longer supported as of September 1, 2021. Please ask your application developer to migrate to a supported version
Nothing to do.