Save of jitter onse/off set

I’m doing an cueing paradigm, the posner paradigm. I have set an intertrail interval to random(1) and then I have in the “data” box choosen “save onset/off set”. However, its not always this is saved and as I’m now starting to move this in the the fMRI, I really need to make sure that I will get the correct trail onset.

I use bottom press with 2 keys. Every other information is saved, so it’s just this trial onset.

Any suggestion to what to do?

Best regards,
Charlotte