I sometimes have the feeling of blocked messages inside Node-Red (currently 4.0.5).
Then some functions -not all- are not working anymore and if I make a full deploy of the flows again, all is working and in e.g. using node-red-contrib-lgtv the messages towards a LG-TV all blocked messages are coming afterwards.
Sorry to be not more detailed. But is this a known Node-Red issue or where can I search for the possible reason of this behavior?
That sounds like you could have a backlog of messages waiting to be processed.
The full deploy would clear out the queue.
Have you checked for runaway loops, including MQTT in and out nodes using the same topic?