The soil looks wet. Do you allow it to dry up before re watering? How often do you water? What direction is that window facing?

Water about every 1-2 weeks. A couple cup fulls. That is a south west facing window

That's your problem, only giving it small measured out amounts of water. When you water any plant, it's always best to flush out the whole pot with plenty of fresh water. Tap water has small quantities of dissolved solids within it, and when you only give a plant small pre-measured amounts that doesn't drain away, then those dissolved solids begin to accumulate in the soil because it has nowhere else to go. This only gets worse each and every time you go to water it again. The water dries up and the dissolved solids precipitate. More and more dissolved solids accumulate, which makes it harder and harder for your plant's roots to function properly.

Another thing that seems wrong is the soil itself. It looks like it isn't a fast draining soil, and that it holds on to too much water. Pachiras love lots of water, but their roots also love lots of fresh air. I would repot it using a fast-draining soil, such as that used for cacti & succulents. And when you water it, always flush out the whole pot with plenty of fresh water.

I agree the soil might be holding too much moisture. It looks to be overwatered so I would hold back on the water letting the roots dry up , and not water until you see new growth. Repotting with new soil asap would help.

Thanks all !