Hi,
I know that this topic already came up here on the forum but I am not sure if the answers apply to my plant. My pachira is sitting on the east facing window, it gets some direct morning light. Humidity is around 50%. It pushes new growth but some leaves get dry tips, others get yellow and fall off. I let it dry out almost completely before watering. Is it under watered? Or maybe humidity level is too low?

It looks like that pot is pretty small and with so little soil it would dry out quickly. I would repot it in a larger pot.

It is hard to judge the actual size of a pot in cache-pot. How wide and deep is it?
My Pachira is double the size (I think) and it is in 7" tall pot, but .. on water wick, so it has moisture at the bottom always, even as the top soil gets dryer with time and needs to be rewetted periodically.
I would say the pot is fine, just take it out of cache-pot to the shower and flush it with lots of water 3-4 times. Then fertilize regularly and flush regularly too: it will leach the salts out of the medium and provide deep drinks.
Older leaves falling off is normal. Especially in spring with more active growth.

I just took a pic of mine : 2.5 years from seed. Originally I plaited 3 trunks, but one was growing much slower and smaller.
So I cut it off: 2 left. Each has 7 leaves still after I removed 3 bottom leaves.
Mine also got some brown tips ( and spots from spraying with soap solution).
It is the width of the door and trunks about 2 feet high.
6 months ago I put it in 1 gal pot. And I intend to keep it in it for a couple of years at least.

I think the issue with your plant is moisture related. Money Tree (Pachira aquatica) and Money Tree (Pachira glabra) are wetland plants. In their native habitats they grow along river banks and in flooded areas. I have two or three Pachira that look awful due to neglect; they are all small container plants sitting outside somewhere on the property. I've thought about planting them in the ground but I have just never done it and I really should consider taking better care of them.