whats the fertillizer your using & your NPK values, did you switch to flowering ferts when you started the flowering cycle?

although the growth spurt is normal, I too think the stretch is excessive between grow nodes, if your too high in nitrogen, this can inhibit flowering and exaggerate the growth sprut from flowering .

additionally 3 weeks in and very little budding .....at 3 weeks most of my strains are almost half way completed.

you may just have a slow strain?