Hi Mate,
Different strains, different needs. You always have a good Chance to not to feed both Lasies properly with the same feeding solution. I'm no Hydro Pro, but your Damsel looks like it's overwatered, when you have too less oxygen at the root-zone.
Maybe the light is too strong for this one. That's also a possibility I would think of.
17cm to a 300w light is way too close IMHO...
Hope this helps a bit, good luck and happy trails for the rest of the way ๐ค
Servusโ๏ธ
OimRausch