What's the issue here?

i think she's a bit stretchy due to the lack of direct light at the early stages (you mentioned there was not too much sunlight in the past), right? and it could be that she's not used to the real direct sunlight once the sun is out, as you said she's curling upwards (which could be a sign of heatstress).. in regards to your mentioned nitrogen toxicity i have to say i don't see anything about this. Nitrogen would make the leaves dark green and that's definitely not the case here. Given she's an auto and in week 5 her current "rapid grow" might already be the stretching during the early bloom stages, so ensure she's getting sufficient food (that still contains nitrogen).. once she stops growing and starts building buds, switch over to the more P and K heavy nutrients (bloom nutrients - whichever you use for it) happy growing