I now have a better understanding of some strange behaviour in my workflows: I realised that an if node wasn't what it seemed:
On display: if myBool is True
In the workflow's sle json: if myBool (boolean) = "up".
In fact, this corresponds to two states of the if node that got mixed up.
At first I put an if myvar="up"
And then I changed it to their user boolean.
The result is an if that mixes the two.
I'm trying not to let this happen too often...