I'm tending to think the problem is a sulfur deficiency.... and your PH might be too high for the plant to absorb this micronutrient. While I would encourage you to lower the PH to a MAXIMUM of 6.3, I'm also going to encourage you to do a bit of research because only you know exactly what is going on with your grow... I've found this one article that will start you off but there are many others out there... https://www.zamnesia.com/grow-weed/89-sulphur
Good luck!