Firstly, when posting flows please insert it inline, but only export as many nodes as are required to exhibit the issue. When pasting flows, in order to make it, readable and usable it is necessary to surround your code with three backticks (also known as a left quote or backquote ```)
```
code goes here
```
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See this post for more details - How to share code or flow json
Have you attached a debug node to the inject and to the reply from the last one in the chain in order to see how long the whole sequence takes? Have you allowed for the time the devices take to respond?
