recording short triggers into a data object using gen does not seem to work

I'm trying to record some triggers into a data buffer using gen, but it appears that this does not work. I guess it's because the triggers are so short. I've included a trivial example to demonstrate this and it appears you need the pulse width to be at least 0.2 for recording to work accurately. Is there something that I need to do differently in my gen code to make this work for shorter pulses?

Please note that increasing the pulse width is not really a suitable fix, as unlike the trivial example attached my triggers are actually generated in another gen patch which is doing [delta]->[abs]->[> threshold] on another signal to generate the output, so there's no easy way to extend the duration (unless someone can suggest something!)