New leaves replacing old leaves

Hi Laura - thanks, very helpful. The issue that also troubles me is the discolouration and thinning (sort of even brownish tone) of the stem of the new shoot if you can see on the photo. The stem sort of collapses and becomes woody. Some other new shoots which had the same, turned black and died back.... not sure what that is

I've adjusted your photo so the problem can be seen more clearly. I don't know what causes it.

It's possible it may need more humidity, more moisture, more light.

Now may be a good time to take it outdoors.

Very grateful for the replies. Will try outdoors!