Yellow nodes on certain plants not all

Jungleboy#1

New Member
Gelato og kush fems started beautiful and are now turning yellow at the top centre of the plant. They’re getting 7.5ml a + b canna coco 10ml rhizotonic and great white per 5L of water. 600w hps lighting 29degrees c and 55%humiditiy. Can anyone help here are photos of plants with and without the new yellow leafs/nodes
 

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