Hi, firstly: Thank you very much for your answer!
Secondly: Let me clear up a few things.
So I am actually not in a loop in the first screenshot. And there are actually two different cases that have to be distinguished here. So at the start of the game, I am setting the position of every unit and then only run “Set valid locations” once. (This is not seen in my picture, and happens through a different set of nodes.) In that case I have the same problem and also have to use a delay for it to work. The second case is the one in my screenshot. This always happens after a single unit has moved, and therefore only that units location has changed, so the problem you are describing in the first paragraph shouldn’t be an issue.
About what you describe in the second paragraph: Unfortunately I tried it, and a delay of 0.01 actually doesn’t work. I think 0.1 doesn’t even work, so it does need to be set to a specific value in order to work. In the case where it is set at the start of the game, the delay actually has to be 1 second in order to work, so there has to be some kind of slower/faster execution issue imo.