It is either a genetic issue or a virus - likely the former. You can give it a couple weeks to see if it gets going properly and starts growing normal leaves, but it might just be a runt that will never grow to same glory as the rest. If it seems to lag horribly behind and continue to grow like this, you might want to opt to just getting rid of it. With a 80x40 tent and only 95W you might end up with better yield by just fully focusing on the other two plants.