Untick "is trial" but a line of data still appears

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1

Dear friends:

I met a strange problem. I desig a phase of training using a loop before formal experiment. But when I untick the “is trial” in loop setting ,a line of data appear before the formal data and record a reaction time, even I didn’t react in training. If I tick the “is trial” in loop setting, then this line of data won’t appear. :face_with_raised_eyebrow:

I’ll be thankful if you could help me.

OS (e.g. Win10): Win 11
PsychoPy version (e.g. 1.84.x): 2024.1.3
Standard Standalone? (y/n) If not then what?:y
What are you trying to achieve?: