Flowering heads keep stretching

Southern

Active Member
Hey there, a few of the heads on my girls are stretching still (stalk stretch right at the top of the heads). I'm not sure whats going on there but so far thereve been flowering for 6 weeks under 1000W HPS. I have about 8 girls, 4 of which seem to be stretching like prescribed above. Also the buds have seemed to form oddly, like some of the calayxs on the buds have fattend out but some are still quite small (on the same bud).

Any advice to what could be causing this? I'll post some pics very shortly
 
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