If your Primavera P6 schedule is set to use the Retained Logic for out of sequence activities and you notice that despite all the predecessors of an activity being 100% complete, the activity’s Start Date is not on the Data Date as one would expect or the Finish Date is much later than the length of the activity’s remaining duration from the Data Date, then you have an out of sequence activity in your schedule network.
If the activity has single predecessor, tracing the out of sequence activity is a piece of cake but when the activity has more than one predecessor, knowing which of the predecessors’ logic to follow is a game of luck and you might end up following all predecessors’ logic relationships just to identify the offending out of sequence activity. And if you have a huge schedule, this might be a chore.
In the YouTube video below, I have outlined a quick way of knowing which of the multiple predecessors to follow to find an out of sequence activity.