Is the purple pretty? Or bad?

[The Bedroom Gardener UK]

If you see brown then turn that plant down

Funny, but very true.

 

[BII]

Genetics (vs. environment) as the cause? It seems highly unlikely for 2 different strains from 2 different breeders to show the same strange (from my experience) purpling due to genetics, particularly with strains not known for purpling.