Any tree "will drop it's leaves" for a healthy number of reasons ..... it's what they're genetically programmed to do as a survival mechanism. Whether or not leaf loss is a minor or lethal problem depends on two factors - the % of leaves lost and the plant's state of vitality when the setback occurs. A few leaves lost from a healthy plant - no big deal; a high % of leaves lost from a plant that had been enjoying good health is a significant setback; a high % of leaves lost from a plant already in decline can be a lethal setback because the plant may not have enough energy reserves to push a new flush of foliage - which carries with it an extremely high probability of collapse. I'm actually grateful for the opportunities you provide others to turn the sweeping statements you make without qualifying them into perfect learning opportunities. Explaining why those statements cannot be broadly applied doesn't take much time and many people benefit from what others say in disagreement with you. Similarly, explaining why many of the offerings you leave are simply erroneous provides additional opportunities to consider more reasoned points of view. Al

I know you've been around the forums for a while, so I'm wondering if you've been monitoring soil moisture levels with a 'tell'? A tell is much more effective than a "moisture meter" or a digital device (a finger). The symptoms do look like there are issues in play which are related to an overly water-retentive soil and or a high level of salts in the soil. Please tell us how you decide when it's time to water, how you fertilize, what you use, and how often you apply the fertilizer. Does your pot have a drain hole? Do you have a set-up so that once water exits the drain hole, there is no possibility of the effluent finding a pathway back into the soil. What kind of temps, light levels, humidity, is the plant dealing with? Water uptake is an energy-driven process, and it takes oxygen in the root zone to burn the food to make the energy. An inadequate oxygen supply = limited root function = an inability to move water to the plants most distal parts (leaf tips/margins) = the manifestation of the symptoms depicted in your images. So, let's wait to see what you have to say, then see if we can determine what needs fixing, then develop a plan to get it fixed. Al

Is there a sticky substance on the affected leaves or on the floor under the plant? Can you take a couple of pictures of the underneath sides of the leaves?

Here is a photo