after update Flatpak version no contacts shown anymore

After updating of the flatpak version of Gnome Contacts to 3.34, it suddenly does not show any of my contacts I have in Nextcloud via Gnome Online Account (GOA). It is simply empty, see picture below

It is in Dutch, it requests to select the main address book for new contacts. In case of online account, one can configure the online account in order to show contacts in Gnome Contacts. That is what the text says. There is nothing to select, no any link.

Using the terminal command gives more information:

$ flatpak run org.gnome.Contacts

(gnome-contacts:3): folks-WARNING **: 20:58:57.819: Error preparing persona store ‘eds:37767f02a8bdd65e2d638adab382585e470a1eb1’: Couldn’t open address book ‘37767f02a8bdd65e2d638adab382585e470a1eb1’: Unable to connect to “Contactpersonen”: The name org.gnome.evolution.dataserver.AddressBook10 was not provided by any .service files

(gnome-contacts:3): folks-WARNING **: 20:58:57.819: Error preparing persona store ‘eds:system-address-book’: Couldn’t open address book ‘system-address-book’: Unable to connect to “Persoonlijk”: The name org.gnome.evolution.dataserver.AddressBook10 was not provided by any .service files

(gnome-contacts:3): folks-WARNING **: 20:58:57.830: Failed to find primary PersonaStore with type ID 'eds' and ID 'system-address-book'. Individuals will not be linked properly and creating new links between Personas will not work. The configured primary PersonaStore's backend may not be installed. If you are unsure, check with your distribution.

In Evolution I have access to address book via GOA.

This issue occurs on both laptops I have. Both with Debian, one with Debian Buster and the other with Debian Testing.

Any thoughts?

update: after the most recent update of Debian Testing, Gnome Contacts shows contacts now. I don't know which update did the trick. Well, I guess I have to wait for a certain update in Debian Buster.