I'm not quite sure what you want to do, but I have some idea. Can you fix it with an else statement?
I think the best solution is to use the System.TriggerOnceWhileTrue condition, which means that each object will only try and change the other when it is first activated. Then Maybe some kind of cooldown timer, depending on what you want to do.
The trigger once seems like it'll help my enter press not be continuously evaluated, which is helpful, but it doesn't seem to help my main problem. I will attach a screenshot of my events for clarity.
As you can see I'm trying to switch the visibility of two sprites if one is active it's visible and two invisible if two is active one should be invisible and 2 should be visible. Right now if I delete the second if then it works but there's no way to get back. I'm trying to set up a toggle on enter pressed, if that makes any sense.