Internal vars are basically a “remote” way of creating value connection links (probably the name is easy to misunderstood).
You don’y really “set” those though. Whenever the “Get Internal Var” is requested, the value will be fetched from the “Set internal var”.
Here is an example to clarify:
Thinking of this, I could add a flow input, so that this acts more in the way you’d expect, that means explicitly setting an internal var only whenever the relevant flow input is called.
Is that how you were expecting this to work by the way?