I disagree to a degree with lampshade. when u flushed, if you did not feed immediately you made the problem worse. if you flush again now, than you will make the problem worse. not much you can do at this point but it is very normal for most strains to yellow even in the presence of proper N amounts. a week or 2 to go, the only thing you can do is look at the trichs-if they are mostly clear with few cloudys, I mean few, than yes give them some veg formula. 1/4-1/2 strength tops.
it is during the first 3-4 weeks that too much N will delay budding. and you would need extremely high levels with light leaks to 'abort' budding.
if the trichs are cloudy with couple amber, than flush or dont flush it makes no difference.
all in all, you sound exactly where you should be. next time, dont cut off the N or lower the N levels until later in flowering, after the stretch