There are so many variables in this that it's hard to just have one answer (of course there may be someone that will say that 'this' is the problem). To begin with almost all ficus are 'touchy' plants, almost any change in the surroundings will cause the plant to react in some manner: leaf drop, wilting, discoloration, etc. The good news is that they will recover. You have changed everything in this plants living conditions, it's reacting.

'Watering as needed' is very loose...like any plant they need watered well to soak the soil in the pot then allowed to drain. Ficus are happy in a lose soil mix which drains well...in a pot which also drains well. They like the soil to be evenly moist but not sitting in water. This will cause root rot for any plant/tree.

The 'wrinkled' leaves can be a sign of over or under watering, the new growth on my latest one (as I stated in a previous post) have been emerging in a 'wrinkled' condition. After a few days this goes away and the leaf looks normal. Also, the new growth has a reddish-bronze coloration running through it, this also dissapears as the leaf grows. Seems to be a trait of the plant and otherwise it's good and healthy.

You can also get a wealth of information by just using Google for plants and associated problems.

Bob

Have you recently moved the plant or changed any of it's other conditions? Ficus are a bit picky about being moved but they are hard to kill without actually trying.
The leaves on ficus will often turn brown if they don't have enough sun, too much sun, too little water...just about any reason, sometimes for no reason. Sometimes it is just low humidity.
Check for spider mites and other pests too, they like the indoor plants and low humidity really brings them out.
Sitting in water is bad for ficus, good for bald cypress.
Hang in there!
Tally HO!

There is a distinct difference between cupped or wavy leaf margins and "wrinkled leaves". I can't imagine the leaves of F religiosa being wrinkled as a drought response caused by a high level of salts in the soil solution, under-watering, or over-watering, so I'm left to think that it might be the leaf margins being described. If so, it would likely be from photo-exposure (high side) or if it's occurring only in new leaves, from one of a couple possible micro-nutrient deficiencies. Not enuf info.

Al

Right and there was no response from the OP so maybe we won't ever know. I have one I just picked up that's doing that but it's clearly a 'trait' of the tree.

The leaves are about the same size as a standard ficus b. but broad like (but not leathery) as retusa. Just a little different.

I've done some searching but with no use.

As I defoliated the tree the new foliage unfurled with a very light green color (twisted and wrinkled too), over a few days they turn a reddish/bronze then stay that color for a few weeks before returning to a normal green.

There's nothing wrong with the tree as far as health. This is just an interesting trait and very pretty when there is a lot of new foliage.

Bob