2 weeks from harvest

got a bit of a problem ........using canna boost and pk 13/14 0n my bb x white widow.Used the nutes on last grow (same plant types) and had good harvesy,no problems.This time 2 weeks from finish, buds arent quite the same size and leaves are really pale yellow....tried a little nitrogen in last feed.....no joy......tried epsom salts.....no joy. I know the plants take "N" out of the leaves but i,ve never seen this happen b4...........any suggestions????? thanks

gonna use these nutes too mate.doing some ak autos,4 weeks to go,already using the booster,not sure about directions of use on the pk13/14...any advice please