Good morning to all! I have a cactus which I had potted last year, it was taken from a cutting from an old cactus tree, possibly even 60 years old. It seemed quite happy and green, and a couple of months ago it also grew three little pups from the top. Last month we noticed that it started turning grey, but the area immediately around the pups still remained green. The grey part does not feel mushy, its still firm as it was when it was still green. We are also in a hot climate here, and in the past month had heatwaves reaching 40 degrees Celsius. We were wondering what could have been the cause for this, and more importantly what to do next. Should we attempt to cut off the green part and pot that separately? Thank you so much!