String item not being restored

Hello. I am using OH 5.1.0 on a synology NAS, in Docker.

I am having the problem that after a restart of the NAS, when the container restarts, all the Items’ states are being restorted, but one. I have one String item whose contents, according to events.log, seem not to be restored for some reason. The item definition is:

String      Betriebsmodus        "Heizung Betriebsmodus"  (Haus)             { channel="knx:device:bridge:heating:Betriebsmodus" }

The item’s value is then null. I have no persistence configuration set, so it should be using the defaults. Does anybody have any idea what might be the problem?

rrd4j cannot do strings, so you would need to use an additional persistence service that can (like mapdb) for restoreOnStartup.

Oh that is an easy explanation. I will take a look at that then.

Now I wonder: Is it possible to use rrd4j for everything but String objects, and use something else for the Strings? But I guess I can read that up… Thanks!