Flatpak org.gnome.Platform runtime Yubikey FIPS smartcard support doesn't seem to work.
I need to be able to use my Yubikey FIPS smart card with flatpak applications. For a long time I couldn't get any flatpak applications to recognize my smart card. Non-flatpak applications worked as expected. Even the yubico application. com.yubico.yubioath, would not see my smart card. Recently there was an update and now com.yubico.yubioath can use the smart card, which is great, but the application that I really need to use is Remmina, org.remmina.Remmina, since there is no other option besides flatpak for Remmina on RHEL 8. I use Remmina to remote into computers that require the smart card to be passed through to login. This is a big blocker for me using RHEL 8 and flatpak in general.
The main difference between the two applications seems to be the runtime.
com.yubico.yubioath org.kde.Platform/x86_64/5.15-21.08
org.remmina.Remmina org.gnome.Platform/x86_64/41
They both have the sockets=pcsc; permission, so it seems to me that there is something about the org.kde.Platform that is able to handle the Yubikey FIPS smart card while the org.gnome.Platform is not.
On other linux distributions like Debian or Fedora where there is normally packaged Remmina the smart card support works without issue, so it is specific to flatpak.