Many vegetables will bolt when they're grown in the wrong season, and this is because they're photoperiod sensitive. This means that for a short-night plant if the night hours drop below a critical period for particular duration eg. month, they respond by flowering and going to seed. This is undesirable as the leaves stop growing, and become bitter e.g. spinach. They probably do this so that their pollen is available to insects which are active at that time of the year.
So, if you wish to plant a short night plant in full shade for part of the day ( at the beginning or end of the day), does the full shade contribute to the hours of darkness and prevent bolting?