[Bug]: Background portal not setup (Flatseal)

[PeterSalsa]

Package

Flathub

Distribution

Linux Mint 21.2

Describe the bug

Reminders doesn't run in the background automatically. I found https://github.com/remindersdevs/Reminders/issues/33 which suggested installing Flatseal and enabling the permission there, however the 'Background' permission is disabled and cannot be enabled.

To Reproduce

1. Install Reminders via Flatpak
2. Install Flatseal
3. Attempt to enable the Background permission

Logs

No response

Additional context

Running Reminders v4.0.

[PeterSalsa]

Not sure if it's relevant, but just noticed this when debugging another Flatpak app:

$ flatpak ps
Instance   PID   Application                   Runtime
3862726548 15060 [REDACTED]                    org.freedesktop.Platform
2590703531 14031 [REDACTED]                    org.freedesktop.Platform
839028253  5348  io.github.dgsasha.Remembrance org.gnome.Platform
2510053395 3307  [REDACTED]                    org.freedesktop.Platform

It seems Reminders is running in the background, but its runtime is org.gnome.Platform whereas all my other Flatpak apps are org.freedesktop.Platform...