There are Salvias, 'Hot Lips' is one, that have different coloured flowers at different times. A cutting is a piece of the parent plant so it will have exactly the same colour genes
Well, it's very strange, that's why I take cutting to have the same plant. The funny thing is I cut back the parent plant in spring like the others and it has sat and sulked eversince with virtually no growth.
The only other thing l can suggest, if you are absolutely certain that you didn't muddle the cuttings up, is to contact William Dyson. He is one of the leading experts in salvias, and might be able to solve the puzzle. I can't guarantee a reply though https://www.dysonsalvias.com/contact-us/
@floralies Overtime Salvias can become very woody and growth can be poor. Maybe the mother plant has just run out of steam. Another top grower is Middleton Nurseries. Hope this is helpful.
Posts
In the sticks near Peterborough
BROWN IS A COLOUR Piet Oudolf
https://www.dysonsalvias.com/contact-us/
BROWN IS A COLOUR Piet Oudolf