NullPointerException when activating item with HTTP-Binding (OH 2.4)

On every activation in the BasicUI, I’m getting a warning in the Log-Viewer:

Item:
String poweroutlet_IT_B_2_Switch_HTTP “Funksteckdose XS1 API” <poweroutlet> { htt§=">[ON:GET:htt§://10.0.0.4/control?cmd=set_state_actuator&name=IT_2&value=1] >[OFF:GET:htt§://10.0.0.4/control?cmd=set_state_actuator&name=IT_2&value=0] <[htt§://10.0.0.4/control?callback=cname&cmd=get_state_actuator&name=IT_2:10000:JS(parse_xs1.js)]"}

Log:

2018-12-27 16:57:40.964 [WARN ] [org.apache.karaf.services.eventadmin] - EventAdmin: Exception during event dispatch [org.osgi.service.event.Event [topic=openhab/command/poweroutlet_IT_B_2_Switch_HTTP] {item=poweroutlet_IT_B_2_Switch_HTTP, bridgemarker=true, command=OFF, timestamp=1545926260935} | {org.osgi.service.cm.ManagedService, org.osgi.service.event.EventHandler}={service.id=375, service.bundleid=210, service.scope=bundle, event.topics=openhab/*, service.pid=org.openhab.http, component.name=org.openhab.binding.http, component.id=31} | Bundle(org.openhab.binding.http_1.13.0.RC1 [210])]

java.lang.NullPointerException: null

at java.io.Reader.<init>(Reader.java:78) ~[?:?]

at java.io.InputStreamReader.<init>(InputStreamReader.java:72) ~[?:?]

at org.apache.commons.io.IOUtils.copy(IOUtils.java:1582) ~[?:?]

at org.apache.commons.io.IOUtils.copy(IOUtils.java:1608) ~[?:?]

at org.apache.commons.io.IOUtils.toString(IOUtils.java:668) ~[?:?]

at org.apache.commons.io.IOUtils.toString(IOUtils.java:646) ~[?:?]

at org.openhab.io.net.http.HttpUtil.executeUrl(HttpUtil.java:202) ~[?:?]

at org.openhab.io.net.http.HttpUtil.executeUrl(HttpUtil.java:130) ~[?:?]

at org.openhab.binding.http.internal.HttpBinding.formatAndExecute(HttpBinding.java:291) ~[?:?]

at org.openhab.binding.http.internal.HttpBinding.internalReceiveCommand(HttpBinding.java:130) ~[?:?]

at org.openhab.core.binding.AbstractBinding.receiveCommand(AbstractBinding.java:94) ~[?:?]

at org.openhab.core.events.AbstractEventSubscriber.handleEvent(AbstractEventSubscriber.java:45) ~[?:?]

at org.apache.felix.eventadmin.impl.handler.EventHandlerProxy.sendEvent(EventHandlerProxy.java:415) [3:org.apache.karaf.services.eventadmin:4.2.1]

at org.apache.felix.eventadmin.impl.tasks.HandlerTask.runWithoutBlacklistTiming(HandlerTask.java:82) [3:org.apache.karaf.services.eventadmin:4.2.1]

at org.apache.felix.eventadmin.impl.tasks.SyncDeliverTasks.execute(SyncDeliverTasks.java:104) [3:org.apache.karaf.services.eventadmin:4.2.1]

at org.apache.felix.eventadmin.impl.tasks.AsyncDeliverTasks$TaskExecuter.run(AsyncDeliverTasks.java:166) [3:org.apache.karaf.services.eventadmin:4.2.1]

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:?]

at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:?]

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]

at java.lang.Thread.run(Thread.java:748) [?:?]

That looks problematic.

You should (as everyone should) get a debug log.