I met a very strange bug.
Attachment 1.png
When I put make collision shape a sensor it maker it a sensor even if this part of code was never executed. You can see this in 1.gif. What I mean is this action is being executed separately even if the rest of code was never executed. No matter what. You can see in log that print dead enemy is print only when an enemy is dead. So the shape should be a sensor only when the command is being printed. As you can see, it becomes sensor without executing the rest of the code.
Attachment 2.png
You can see that when I disable this action (make a sensor) it never becomes a sensor. It proves that what I stated above is true. Please look also at 2.gif to see that it really is. I don't know if this problem exists only in my project, but it really is serious.