workAreaStart and workAreaDuration behaviour in ExtendScript

I found a workaround.

In order to get this to work, you need to create a for loop separatedly where you go through all the CompItems and define the workAreaStart and Duration inside each pre comp.

Make sure that your times are Timecode (0:00:00:21) and you use currentFormatToTime when setting the times for workAreaStart and Duration.

   for (t = 1; t <= app.project.items.length; t++) {
        if (app.project.items[t] instanceof CompItem) {
           
            if (app.project.items[t].name != "main") {
                compSelected = app.project.item(t);
               
                var timesToSelect = String(compSelected.markerProperty.keyValue(1).comment);
                var timesForSelection = timesToSelect.split("-");
           
                timeStart =currentFormatToTime(timesForSelection[0],currentComp.frameRate);
                compSelected.workAreaStart = timeStart; //in seconds
                calcWorkAreaDuration =  currentFormatToTime(timesForSelection[1],currentComp.frameRate)- currentFormatToTime(timesForSelection[0],currentComp.frameRate);
                alert(calcWorkAreaDuration);
                compSelected.workAreaDuration = calcWorkAreaDuration; //in seconds
            }
        }
    }

can confirm similar behavior in the latest AE - it takes several runs to set the correct workareastart and duration.

I tried a little more but still don’t understand what is going on.

Sometimes Comp2 gets the identical workareaStart, other times the script needs to run a few times to get to the right start position.

For this test you need a new project with 2 new empty comps.

var sourceComp = app.project.item(1);
var destComp = app.project.item(2);
destComp.workAreaStart = sourceComp.workAreaStart;
destComp.workAreaDuration = sourceComp.workAreaDuration;