sir_isOanswered grow question 4 years ago Dude, just let that thing keep growing.
It's actually not that you're doing something wrong, it's that they're so happy that they can grow for longer. Remember, autoflower lineage is from plants used to very stressful conditions, so when they get really good conditions, they might grow longer/larger/better.
Take it as a sign that you're doing REALLY well.