Sorry, on closer looking at your plant there is bistering and is also very shiny. Here is a list of what can cause these issues without it just being a thing of just happening, where in this case, looking at your leafs, I just don't like that bistering and without nutes, PH for weeks and what you are growing in. It's hard, to say its this or that. Read this and maybe put up a detailed diary for more help. https://sensiseeds.com/en/blog/understanding-identifying-and-using-cannabis-leaves/