MQTT issues with dynamic subscribtions

Hello,
I'm using in and out mqtt nodes with dynamic subscribtions.
Through my dashboard I can type broker IP, ports and credentials and I've connect and disconnect buttons.
It's working fine if the connexion can be established.
However, if I type a wrong setting like an ip of a non-existing broker, nodes are sometimes stuck on "connecting". Sometimes goes to "disconnected". The problem is when I came back to an existing broker and I try to connect, the connexion cannot be established ! I've to restart flows in the deploy menu in order to connect. No problem for disconnecting and connecting to existing brokers....
What should I do ? Is there a problem with those nodes ? With something else ?
Before connecting, I disconnect. When disconnecting I also unsubscribe from topics (2 queued msg with 1 sec delay). After 4 sec, when connecting, I send a msg to connect to the broker with settings, and another msg to subscribe to a topic. Waiting for help ^^...

All of these issues are fixed in GitHub but not yet released. If you are willing to install v 3.0.0-beta.2 you will see the improvements. If you, I would appreciate feedback either way. Ta.

Ok thanks, I'm not admin of the node-red application so I will see if it's possible. Have a nice day !