I just read your diary and you have them on a 20.hr light schedual, this is likely your issue, your DLI is way off and your VPD is a bit off at 1.19 and it should be between 0.96 and 1.15 you're in to the stress range of the VPD chart and ill venture a guess that they're not on a proper watering schedual either, over watering is what ill lean towards, let them dry up a bit change your light schedual to 18/6 and lower your temp by 1c or raise your humidity up 1% to get you right in the sweet spot of the VPD chart at 1.12 and see of those slight changes make a difference and cut back on the water...See what happens in 24 for 48 hours and if nothing changes let us know...but I think those changes will make a difference