Just wondering what this could be? I've been using 1tsp of grow big and 1 1\2 tsp of foxfam plant food....it's been 2 months and 2 week in veg and I

Just wondering what this could be? I've been using 1tsp of grow big and 1 1\2 tsp of foxfam plant food....it's been 2 months and 2 week in veg and I just switched them to flowering yesterday...but the bud sites seems to be turning yellow with a few burt spots... could this be a cal mag issue?

Just wondering what this could be? I've been using 1tsp of grow big and 1 1\2 tsp of foxfam plant food....it's been 2 months and 2 week in veg and I just switched them to flowering yesterday...but the bud sites seems to be turning yellow with a few burt spots... could this be a cal mag issue?