Error 500 with Tado-API and HTTP-Binding

Hello,

i actually got a problem, that i really dont understand.

I am using the Tado Smart Thermostats in openhab with the http-binding and the tado-api. In genereal it works well and i got no problems with it.

Today i added two values from the api - both values are very similar but one of them causes an error - paperui says internal error 500 and the habpanel says that the connection is lost.

Here the two new items i created today:

String tado_wohnzimmer_manuelleSteuerung "Manuelle Steuerung Wohnzimmer" { http="<[tado_wohnzimmer:60000:JSONPATH($.overlayType)]" }
String tado_wohnzimmer_HeizungAn "Wohnzimmer Heizung an" { http="<[tado_wohnzimmer:60000:JSONPATH($.setting.power)]" }

Here the json-output if the zone is in the manual mode (first item) and an opened window is detected (second item):

In this case everything is fine an i got no errors.

When there is no open window recognized, the json-output looks like this:

In this case even everything is fine, in spite of the missing value "JSONPATH($.openWindow.remainingTimeInSeconds)"
No errors.

When i exit the manual mode, the json-output looks like this:

Now JSONPATH($.overlayType) switched from “MANUAL” to NULL - and now i got the mentioned errors.

I dont understand it, because in both cases the value switch from a value to NULL and in one case it is a problem and in the other not.

Do you have an idea whats going wrong here?

Thanks a lot,
Alex

PS:
In the logfile the value were changed correctly:

22:06:47.652 [INFO ] [marthome.event.ItemStateChangedEvent] - tado_wohnzimmer_HeizungAn changed from OFF to ON
22:06:48.588 [INFO ] [marthome.event.ItemStateChangedEvent] - tado_wohnzimmer_manuelleSteuerung changed from MANUAL to null

i think i can detail the difference a bit better now, but its still not clear for me why there is a different handle and how i can solve ist:

{"tadoMode":"HOME","geolocationOverride":false,"geolocationOverrideDisableTime":null,"preparation":null,"setting":{"type":"HEATING","power":"ON","temperature":{"celsius":18.00,"fahrenheit":64.40}},"overlayType":null,"overlay":null,"openWindow":null,"link":{"state":"ONLINE"},"activityDataPoints":{"heatingPower":{"type":"PERCENTAGE","percentage":0.00,"timestamp":"2017-06-11T20:12:42.451Z"}},"sensorDataPoints":{"insideTemperature":{"celsius":23.38,"fahrenheit":74.08,"timestamp":"2017-06-11T20:11:20.915Z","type":"TEMPERATURE","precision":{"celsius":1.0,"fahrenheit":1.0}},"humidity":{"type":"PERCENTAGE","percentage":63.90,"timestamp":"2017-06-11T20:11:20.915Z"}}}

It makes no sense for me, that the overlaytype is shown in the rest-api as “no content”, in spite of the value “null”, during the $.setting.power is no longer included in the json-string but has in the rest-api the value “null”
“overlayType”:null,