I could be wrong.. But that looks like the same issue I had earlier in my current grow.. Do you have a fan blowing on the plant? It looks like no.. When the lights go out, they tend to transpire a bit and if there isnt a fan, the transpiration will leaves drops like that on the edge of the leaves.. I had my power go out and that's what I saw.. When the lights turn on it creates a magnifying glass and will burn those spots where the drops are left till they dry off.. But again.. I could be wrong.. But that's what it looks like to me.