Same participant did the survey twice

I have had a participant who started and submitted at a very similar time for the same survey twice in my study. I used embedded data to record Prolific ID, so the account must have been login at two places. Anyone had that issue before? Does anyone have any idea why is that happening? I am guessing some people might be sharing the same account?

Haven’t seen that, but your explanation seems likely: Perhaps message the person(s) and ask…?