If it's only the old leaves, and the new leaves are good, then it's just the normal process of senescence. But make sure your soil isn't staying too wet. Some Alocasias like to stand in water, some will die in it. Yours are in the category of not liking it wet, they just need it damp.

That photo doesn't look like normal nitrogen deficiency to me. I think it may be a potassium or micro-nutrient deficiency. I'm just guessing without knowing more about what they're growing in. The beans sound to me like aphids and spider mites. check the underside of the spotted leaves for small red arachnids. My bitter melons took a long time to do much of anything but the weather warmed up for the past couple of months and I have fruit bursting all over now.

What is the soil like? When you check the dryness of the soil it it only on the surface or are you checking deep down in the pot? Do you water until it runs out the bottom?

Hi everyone. Unfortunately Monstera deliciosa has more culture myths floating around than almost any other plant. The "bright indirect light" myth is the worst. It's everywhere on the internet and it's pure hogwash! :) Most all of the biggest-leaf, massive, mature specimens get from several hours a day full sun up to all-day sun, outdoors. You just really can't give it too much sun if it's grown indoors as a houseplant, unless you switch from low sun too quickly and sunburn it. Next is the "fast draining soil" myth. Many plants love that, and Monstera do great that way, but there must be some houseplants that don't absolutely require it as much as others, right? Monstera deliciosa is that plant. It will grow extremely well in wet mud, in plain clay garden dirt in a pot, and yes also in premium free-draining expensive media too. Another myth are the extreme cautions about being so careful not to overwater it. There is hardly any houseplants that can resist overwatering more. You probably can't overwater it unless your pot has no drainage hole and the soil goes anaerobic. It is still optimal to provide constantly moist-but-not-wet soil, but it's usually UNDER-watering that causes these types of leaf die-off. The last myth is the "increase the humidity" myth. It's great, but just not necessary. They have a tough, thick outer skin and can resist low humidity very well. This one below is grown in a northern heating climate with a central forced-air furnace that really drys the air all winter, often below 20%, yet it doesn't have any brown edges. It gets watered about once every 4 days right now (it needs a bigger pot soon!). It gets lightly fertilized with Foliage Pro at every watering throughout the year. So the plant in the first post needs more sun and more water. Ideally it should be right up in an E, W, or S window (those super-long petioles are etiolating, which is evidence the light is way too low). It needs to have the soil flushed deeply once in awhile, in case that is partially mineral salts fertilizer burn. Also, I would recommend you consider switching to a low-urea liquid fertilizer (like Foliage Pro or similar) more frequently and lightly, as these don't have the strong salt-based ingredients that burn so easily. One concern I had: I do want to know what you mean by "houseplants compost". Thank you. :)