Autoflower Power

Not sure, looks like damage from the fan or just a damaged leaf. Don't think it's a nutrient issue.

24-42 days. That's when I believe you'll be in your harvest window. Amnesia usually goes around 12 weeks into flowering so I would guess the later side of this estimate.

Judging from the burnt tips of the leaf and discolouration I would say that’s over feeding with the nutrients. Also looks like the leaves look a little prickly and almost turning up so could be a slight heat problem starting although I see your temp is about 26 which should be ok. If you have not already try and have a fan blowing in between the light and plants etc. I have also seen the leaves almost mimic slight heat stress from going too high with the EC/ppms. My first move would be to drop the feed strength and also try and drop the temp a touch to rule that out too. Hope that helps pal👍