What is wrong with my chamaelobivia cactus?

Hi!
I got this chamaelobivia cactus from a garden centre two weeks ago. We’ve had some nice weather here in the UK (8 degrees Celsius on a night, 22+ degrees celsius during the day), and on the packaging it said it would be happy for the light outside. Since it’s been outside, the tops of the plant have changed colour... (picture attached), I’ve only watered it once, it has good drainage and has been in the sunlight quite a lot. Can anyone tell me what’s wrong or what I can do to help it? Thank you!

 

Many cacti become reddish in strong light, and that looks normal. But the thin, pointy new growth indicates too low light, so I am not sure how to interpret this. Sunlight + cooler nights usually has the opposite effect, this plant looks as if it has spent two weeks in a dark but warm spot indoors.​

 

Thanks for your reply, could that may be with it being inside the garden centre where it didn’t get much light before? Or since I’ve had it two weeks is that not possible? It is a little odd!

 

Yes, that is something I see quite often in garden centres.

Certainly possible in warm conditions and low light. I have seen cacti grow that much in one week inside a cardboard box ...
If I had to guess I would say that this happened in the garden centre, it is not normal for a cactus to grow like that outside.