Some sliders on ios don't work anymore

Hi all,

again after 2019 some sliders in my openhab ios app do not work anymore while others still do and while the exact same sliders in basic ui (called via browser) are functional.

The sitemap is defined as:

Slider item=rolloBuero

The items are like this:

Number rolloBuero    "Rollo Büro [%d %%]"     <rollershutter>   (gRolloBuero, gRolloZeit, gRolloNord, gCalItem)                     {alexa="Blind.RangeValue" [capabilityNames="@Setting.Position", supportedRange="0:100:1", unitOfMeasure="Percent", stateMappings="Closed=100,Open=0:99"], channel="http:url:duofern:ChannelDuofernBuero"}

These items are calling http things which are defined as follows:

Thing http:url:duofern "DuoFern" [ baseURL="http://duofern.home.lan:7777", refresh=10, timeout=15000 ] {    Channels:

    Type number: ChannelDuofernBuero        "Rollo Büro"        [ stateExtension="device.do?did=49f497&cmd=getStatus", stateTransformation="JSONPATH:$.device.position", commandExtension="device.do?did=49f497&cmd=position&goto=%2$s" ]

}

After moving a slider the log says:

09:24:55.095	INFO	
openhab.event.ItemCommandEvent
Item 'rolloBuero' received command 36.0 (source: org.openhab.ios$420C1A9B-8842-471C-AD5C-13AE03001F01=>org.openhab.core.io.rest)
09:24:55.096	INFO	
openhab.event.ItemStatePredictedEvent
Item 'rolloBuero' predicted to become 36.0
09:24:55.097	INFO	
openhab.event.ItemStateUpdatedEvent
Item 'rolloBuero' updated to 36.0
09:24:55.097	INFO	
openhab.event.ItemStateChangedEvent
Item 'rolloBuero' changed from 0.0 to 36.0 (source: org.openhab.core.autoupdate.optimistic)

...

09:25:02.413	INFO	
openhab.event.ItemStateChangedEvent
Item 'rolloBuero' changed from 36.0 to 0 (source: org.openhab.core.thing$http:url:duofern:ChannelDuofernBuero)

Again: My sitemap, items and things are fully functional from basic ui since years and have been in ios app weeks ago. Other sliders (e.g. for hue lights or zwave dimmers) are working absolutely fine.

I uninstalled and reinstalled ios ap but without success. I changed to real-time sliders (normally off) but again without success.

What can I do to fix this?