this is definitely overfeeding and not a deficiency... the dark green leaves indicate too much nitrogen..
you said you only fed her once in the entire grow, which could still be a bit too much, in case of pre-fertilized soil..
also during the mid-to-late flowering phase the plant doesn't need much nitrogen anymore (compared to the veg-phase, or the beginning of the stretch phase in early bloom)
Given you grow on soil, i suggest reading this about fertilization: https://www.mandalaseeds.com/Guides/Fertilizing-Smart-Guide even when it might not really apply directly, when you use pre-fertilized soil, however the pre-fertilization might still be too strong for your specific environment.