When watering plants, never give them small, measured out amounts of water. You want to flush plenty of water through the soil. When you give them small amounts of water, the small traces of minerals that are dissolved in that water have nowhere to go and eventually begin to accumulate in the soil. I would suggest moving your plant to somewhere where you can flush the soil out with lots of water and let it drain away. Then perhaps flush it out again later on. Your plant may be in need of a good repotting into some fresh, fast-draining soil.

That your plant needs staking is clear indication it wants more light. Whether or not you can GIVE it more is the question.

The visual symptoms of over-watering and under-watering are the same; this, because both result in the plant's inability to move enough water to the leaves. Both cause leaf abscission (shedding) and wilting. If your habit runs to watering while you can still detect moisture in the soil with your finger, you're over-watering. If your plant has dried down to the point of wilting, under-watering might be a player in the drooping because leaves of F elastica, once they've lost turgidity, are often unable to recover to their former spatial position. This would also explain why the newer leaves haven't developed a pendulous habit. Over-watering causes the same symptoms.

I'd start monitoring moisture levels in the soil with a wood dowel rod, ends sharpened in a pencil sharpener. Stick it deep into the pot - if it comes out stained dark or wet, withhold water. Do flush the soil, as suggested, by pouring a volume of room temp water equal to at least 10X the volume of the pot it's in slowly through the soil. Fertilizer is important. Fertilize immediately after flushing the soil with an appropriate fertilizer. Foliage-Pro 9-3-6 is a very good choice as your 'go to' fertilizer for all your houseplants.

One of the first symptoms or root congestion is lack of extension (lack of visible growth). I'd make a plan to repot next June, if you're in the northern hemisphere, hopefully into a medium that allows you to water correctly w/o worrying a prolonged period of soil saturation will limit root function and/or wreak havoc on root health. If you have concerns about the effects watering correctly might have on your plant, let me know and I'll help you mitigate any potential limitations.

This is just me, but I would have pruned the plant several times to ensure it was self supporting. Shorter plants can't flex as much as a taller plant, so shortening the trunk is essentially a quick way to strengthen it.

Al

Wow! That is beautiful where did you get it. I got 2 off of eBay that were in very bad shape and later I found something eating the roots and the plant died soon after. I don't ever see them anywhere else

Pretty plant!!