If 'it has never been repotted or potted up' the plant would have a tendency to shed older leaves much earlier than would a plant that was situated in a pot such that its roots had room to run. There are several potential answers to your questions, but figuring out the actual cause:effect relationship might be more difficult than focusing on making sure you have the plant's basic preferences well covered.

Have you been fertilizing? flushing the soil at regular intervals? While a nutritional issue probably isn't to blame for the plant's 'floppy' appearance, it very likely could be the reason for the light or mottled coloration, if indeed that's not a genetic issue common in all new foliage.

I'm not suggesting you repot this plant today or even next month. Over the long term, I'd establish goals that include a full repot (June) into an appropriate medium (one you can water to beyond saturation w/o having to be concerned the soil will stay wet/soggy so long it wreaks havoc with root function/health), monitor closely and get control over watering practices, and get the plant on a good nutritional supplementation. In fact, all your plants would be served well by that exact strategy ...... and I'm sure you'd be very pleased with your newfound ability to maintain all your plants in good vitality. You'll usually always find the best potential to regain the most ground when trying to resolve the adversities your plants fact when you focus on the basics. Once you have the3 basics under control, you can branch out and fine tune your strategies if you like. Surprisingly though, I treat all my plants the same way - the only significant difference being how often they are watered - but even that is simplified because I'm able to do that on a rather rigid schedule.

Al