Hi @esteimle
sorry to confusing you. I had a chat with another colleague and he thinks that you are not subscribed to proxy topic - you are just connected to device and then you are reading the proxy positions. You need to be subscribed to that topic to not to get disconnected from the node.
See this post: Bluetooth disconnects after certain amount of time - #2 by maxbauer
Let me know if it help.
Cheers
JK