Empty solution in event detection

I am solving a DAE system and I am using an event function to restart the solving process at each discontinuity, which are triggered by the event function.

It does not seem to work right, as the event is only detected sometimes (Problem 1).

Moreover, it strangely still stops the solving process event when no Event is detected (Problem 2). I do not know how can this be. In this case, the event solutions are all sol.xe = sol.ie = sol.ye = [ ].

The events are supposed to be detected when u_k1-u_k2 = 0 and when Iak = 1. (I used directions to detect the events on a single direction).

Notice that the graphics shows with a red DOT where the event ocured. In the last point, it does not show the event. I did not continue the solving process in the example below in order to show you more clearly that the integration was actually stopped, but no event was detected (sol.xe,ie,ye = [ ]).

If somebody could explain me what could I be doing wrong or missunderstanding, I will be very gratefull.

Thanks, Nicolas