Blue actions not syncing to iCal
 

I'm not sure if I've had this problem before or not. I discovered this morning that of the actions in context view, the blue ones (which are next actions in parallel projects) are not syncing to iCal. The purple ones, the next acctions, are syncing. I've looked over the preferences and can't find something that needs to be checked (or have missed it).

Those not syncing are in contexts that include purple ones. But only the purple ones are syncing. All the blue ones (and most purple ones) have no due date but all have a start date that is not in the future.