hey there Mom, this is basically calcium deficiency from the slightly high pH you got going, the slightly intense light schedule, and the fact that since these plants are really well dialled in, they went into over drive and started needing more micro nutrients to compensate for their growing. you simply need to get that pH down to around 5.8/5.9 and up the calcium/magnesium you have to around 1ml maybe even 1.5 ml dont worry you cant really over do it on calmag, should recover within 5-10 days . hope this helps ! 🚀