problems with digikam Version 5.9.0 Debian Buster and external database

In my setup I use 3 machines, one as NAS and mariadb server, my laptop and one headless called Rechenknecht. All pictures are stored at the NAS on a Raid 1, the database is stored in the usual path on a ssd. So long so fine. Most time I work on the Laptop. Another installation is found on the headless one, there i start digikam with ssh -X. This all works fine. Now my idea was to let the headless one to search faces and tag them. It works. But on my laptop there are the tags, but no faceareas. Both, the laptop and the headless, are configured to use the same database on the NAS. Any ideas why on the laptop not all tags and areas are available? Other Tags, in German called “Stichwörter” are also not syncron.