Wow, it is puzzling. It doesn't look like an ower-watering issue to me, but since we're not coming up with any more likely possibilities, then it is something to consider. This late in the year, it has likely stopped growing, even in Florida temperatures. Pothos tolerates drying out pretty well, so let the top couple of inches dry between waterings. How long have they been in that soil? Did they grow well all summer? If so, they might be a bit pot bound now, which can cause some dry spots in the soil, or some roots to become so restricted that they aren't able to draw enough water. It isn't the best time of year to re-pot, especially if something else is causing the problem, but you should at least check this. Can you pull the entire plant out of the pot with the soil and rootball intact? If so, a photo would help us. Check the root ball and medium for dry or mushy spots, for discolored or necrotic roots, for root parasites, crowding, etc. A few, small disrupted places in the root ball where you dig in to check the condition won't hurt it, even this time of year, and if it's very pot-bound, you can plop the entire thing into a larger pot of soil until the spring when you can do a better job or repotting, detangling, root-trimming, and so on. What parts of the plant are affected the most? Were the oldest/lowest leaves on each stem affected first/worst/most, or is the damage worse on the younger, more tender leaves? Are there any parts of the plants that aren't affected? When was it last fertilized, with what, and how often? (Do not fertilize it now- that's the worst thing one can do to a sick plant if the illness isn't due to fertilizer nutrient deficiency.) It might just be lighting, but the plant in the upper photo appears to have an overall yellowish pallor. That would support Tiffany's hypothesis of too much water. Also, I see a yellow leaf near the base of a stem in the second photo near that little sprig of Acacia or whatever it is that's taken root there. Some yellowing is normal, but check through the lower leaves for more yellowing. Too much water or nitrogen deficiency both tend to affect older/lower leaves first. Evenly yellowing lower leaves is more indicative of too much water or poor drainage, while yellowing that begins at the leaf margins is more often nitrogen deficiency. Other things can cause yellowing though, and that curious staining appearance isn't typical of either issue, so don't fertilize at this point. More photos wouldn't hurt: Entire plant Root ball free from the pot Close-ups of the "stains"

I'm just hoping it's damage from how it was shipped to me. Some of the leaves look fantastic whilst a few are like in the photo. I had to cut off one of the stems which had completely died, it was extremely dry and wood-like and I think it may have been damaged. I might replant it as I used a mix of the soil it came in and the soil I'm using for the terrarium, but it feels a bit too loose. I hope it's not any fungal infection, the springtails should be able help with removing it if it is. I chose this vine as it's a species native to where my reptiles came from, and since it uses rhizomes for attachment, was wanting it to attach to the terrarium wall. I hope it can be saved as it looks beautiful.

Probably just some physical damage. Don't snip it off. It's a fully functioning photosynthesising leaf. The plant needs it.

I was referring to potential damage that might have occurred between point-of-sale and your home. You didn't mention how deep the pot is, so I'll just say watering any plants in pots deeper than about 3-5" using that the top inch or two of soil is dry, is more often than not a recipe for over-watering. After a thorough watering, most bagged grow media will support a 3-6" layer of soil 100% saturated with water at the bottom of the pot. A 10" deep pot could easily still have 6" of 100% saturated soil at the bottom of the pot when the top inch or two feels dry. It's far more important to know what moisture conditions are at the pot bottom, and a moisture meter isn't a reliable tool for that; instead, a sharpened (in a pencil sharpener) wooden dowel makes a much more reliable tool. Using a 'tell' Over-watering saps vitality and is one of the most common plant assassins, so learning to avoid it is worth the small effort. Plants make and store their own energy source – photosynthate - (sugar/glucose). Functioning roots need energy to drive their metabolic processes, and in order to get it, they use oxygen to burn (oxidize) their food. From this, we can see that terrestrial plants need plenty of air (oxygen) in the soil to drive root function. Many off-the-shelf soils hold too much water and not enough air to support the kind of root health most growers would like to see; and, a healthy root system is a prerequisite to a healthy plant. Watering in small sips leads to avoid over-watering leads to a residual build-up of dissolved solids (salts) in the soil from tapwater and fertilizer solutions, which limits a plant's ability to absorb water – so watering in sips simply moves us to the other horn of a dilemma. It creates another problem that requires resolution. Better, would be to simply adopt a soil that drains well enough to allow watering to beyond the saturation point, so we're flushing the soil of accumulating dissolved solids whenever we water; this, w/o the plant being forced to pay a tax in the form of reduced vitality, due to prolong periods of soil saturation. Sometimes, though, that's not a course we can immediately steer, which makes controlling how often we water a very important factor. In many cases, we can judge whether or not a planting needs watering by hefting the pot. This is especially true if the pot is made from light material, like plastic, but doesn't work (as) well when the pot is made from heavier material, like clay, or when the size/weight of the pot precludes grabbing it with one hand to judge its weight and gauge the need for water. Fingers stuck an inch or two into the soil work ok for shallow pots, but not for deep pots. Deep pots might have 3 or more inches of soil that feels totally dry, while the lower several inches of the soil is 100% saturated. Obviously, the lack of oxygen in the root zone situation can wreak havoc with root health and cause the loss of a very notable measure of your plant's potential. Inexpensive watering meters don't even measure moisture levels, they measure electrical conductivity. Clean the tip and insert it into a cup of distilled water and witness the fact it reads 'DRY'. One of the most reliable methods of checking a planting's need for water is using a 'tell'. You can use a bamboo skewer in a pinch, but a wooden dowel rod of about 5/16” (75-85mm) would work better. They usually come 48” (120cm) long and can usually be cut in half and serve as a pair. Sharpen all 4 ends in a pencil sharpener and slightly blunt the tip so it's about the diameter of the head on a straight pin. Push the wooden tell deep into the soil. Don't worry, it won't harm the root system. If the plant is quite root-bound, you might need to try several places until you find one where you can push it all the way to the pot's bottom. Leave it a few seconds, then withdraw it and inspect the tip for moisture. For most plantings, withhold water until the tell comes out dry or nearly so. If you see signs of wilting, adjust the interval between waterings so drought stress isn't a recurring issue. Al