LGTV-Binding: envelope=null

After a bug has been fixed in the LGTV binding, I don’t get an exception anymore when connecting to my TV.
I tried to insert some buttons to start LG apps from openhab, but the only result I get is the following log entry:

[ERROR] [binding.lgtv.internal.LgtvConnection] - envelope=null maybe not connected

Here’s the item definition:

String LGTVWZ_AppStart          "Start"                          {lgtv="*:LGTVWZ:APP_EXECUTE"}
String LGTVWZ_AppStopp          "Stopp"                          {lgtv="*:LGTVWZ:APP_TERMINATE"}

And here’s the sitemap:

        Switch item=LGTVWZ_AppStart mappings=[YouTube=YouTube, LOVEFiLM=Prime]
        Switch item=LGTVWZ_AppStopp mappings=[YouTube=YouTube, LOVEFiLM=Prime]

And idea what I could change to make this working?
Here’s the relevant logfile part:

2017-12-26 14:05:43.063 [DEBUG] [lgtv.lginteraction.LgTvMessageReader] - sendtohandlers remoteaddr= message=VOLUME_CURRENT=14

2017-12-26 14:05:43.069 [DEBUG] [ab.binding.lgtv.internal.LgtvBinding] - Received status update 'VOLUME_CURRENT=14' from ip for deviceId LGTVWZ

2017-12-26 14:05:43.074 [DEBUG] [ab.binding.lgtv.internal.LgtvBinding] - Received status update 'VOLUME_CURRENT=14' from ip for deviceId LGTVWZ

2017-12-26 14:05:43.080 [DEBUG] [ab.binding.lgtv.internal.LgtvBinding] - Received status update 'VOLUME_CURRENT=14' from ip for deviceId LGTVWZ

2017-12-26 14:06:11.512 [ome.event.ItemCommandEvent] - Item 'LGTVWZ_AppStart' received command LOVEFiLM

2017-12-26 14:06:11.519 [DEBUG] [ab.binding.lgtv.internal.LgtvBinding] - Received command (item='LGTVWZ_AppStart', state='LOVEFiLM', class='class org.openhab.core.library.types.StringType')

2017-12-26 14:06:11.524 [DEBUG] [binding.lgtv.internal.LgtvConnection] - send to tv ip= command=APP_EXECUTE type=8 val=LOVEFiLM lgsendparam=

2017-12-26 14:06:11.528 [ERROR] [binding.lgtv.internal.LgtvConnection] - envelope=null maybe not connected

2017-12-26 14:06:11.562 [vent.ItemStateChangedEvent] - LGTVWZ_AppStart changed from YouTube to LOVEFiLM

2017-12-26 14:06:42.944 [DEBUG] [binding.lgtv.internal.LgtvConnection] - sendtotv: url= typ=GET command=udap/api/data?target=volume_info s=

2017-12-26 14:06:42.981 [DEBUG] [binding.lgtv.internal.LgtvConnection] - <?xml version="1.0" encoding="utf-8"?><envelope><dataList name="Volume Info"><data><mute>false</mute><minLevel>0</minLevel><maxLevel>100</maxLevel><level>14</level></data></dataList></envelope>

2017-12-26 14:06:42.998 [DEBUG] [binding.lgtv.internal.LgtvConnection] - answer: <?xml version="1.0" encoding="utf-8"?><envelope><dataList name="Volume Info"><data><mute>false</mute><minLevel>0</minLevel><maxLevel>100</maxLevel><level>14</level></data></dataList></envelope>

P.S.: The pairing was successful:

2017-12-26 13:44:34.357 [INFO ] [binding.lgtv.internal.LgtvConnection] - lgtv connectionstatus of ip= changed from CS_NOTCONNECTED to CS_PAIRED

2017-12-26 13:44:34.453 [INFO ] [binding.lgtv.internal.LgtvConnection] - sendpairkey with result=200 successconnectionstatus=CS_PAIRED

I have the same problem - paired successfully, when I send an App_Execute command (“Internet”), I get the envelope=null error. Once I’ve manually opened the browser on the TV, sending a Browser URL (as in the binding instructions), doesn’t do anything, and doesn’t generate an error.