Physiologically, lots of internal processes were pushing the tree towards the production of new pinkish leaves that made it stood out amongst a background of green foliage.
I was informed that this is a Maniltoa lenticellata var. lenticellata (common name: Silk Handkerchief Tree, Cascading Bean; Family: Fabaceae/Leguminosae), and it was the only one of this size that we had. We have not come across another one of this variety elsewhere in Singapore. At least not yet. In fact, we had been working with the research institution to see if they are able to do a tissue culture of this tree, so that we can eventually propagate it in masses and plant it out in our landscapes.
A link on the species is shown here: