If someone is added at separately twice will they run through the nurture stream twice?

Right now, my company is starting up an engagement program and we will be adding people manually to it. If, for some reason, we don't catch a duplicate person (same information) will they go through the nurture stream twice. Let's say we initially add Jane Doe and 4 weeks later she gets into our list again. If we don't catch her, will she start going through the nurture stream again?

Thanks in advance for your help and suggestions!