Unity UI Eventsystem UI issues

I'm having issues with all versions I have tried so far.

Let's start with 2018.3.14f1: whenever I press the horizontal axis while pressing aswell the vertical axis, the navigation system would fail randomly for some reason. My UI is only vertical and should not react to horizontal axis being pressed in any way...

So I went to 2019.1.3f1 to see if that issue was solved. Ok, not only it is not solved, but I have more errors: sometimes my Eventsystem will not read my controls properly and will not react even if I only press my vertical buttons. I managed to figure out that this was due to my script disabling "Send Navigation Events" after pressing a button. (I needed that for a reason). Ok, I had to wait for a frame to disable "Send Navigation Events" and have my UI working properly again. But the first issue with the horizontal axis didn't dissappear.

The same happened with 2019.3.0a2