hey there, good question ! what happened is you've been slightly over watering this whole time so the soil stayed humid longer than it should eventually leading to root issues. Sounds worse than it is. So you can tell there's some overwatering based on the puffy space between the veins of your leafs, and more recently the slight undercurl. This lead to adverse microbial life making a home in the soil. this in turn affected the roots and this is what leads to the curling of the leafs. To remedy this, nothing easier, just water a few pints less and wait a bit longer between waterings, i would suggest the bag lifting method, but as you've got big bags, maybe use a hygrometer theyre very cheap, you just stick it in to see how dry it is below the surface, and it doesnt really matter if you break roots as you stick it in there as the plant quickly grows new ones. Beyond these preventative measures, I do suggest watering with an enzyme or other chelation agents to break down the problem roots and remedy the problem , try the flower booster (which is just humic and fluvik acid), or a tiny bit of flushing agent, unless you have a product like cannazym on hand, i dont sell the stuff by the way, just one from the top of my head. Hope this helps ! 🚀