Looks like a poorly made cable. Thank goodness the cable is detachable. You should contact moondrop and have them send you another one. For the price this shouldn't happen without something specific.
the only other thing I could think of is that you may be storing them in a configuration that puts stress on the cable. Otherwise even the crappy moondrop cables shouldn't break this quickly.
I recently quite literally broke the cable of my SSP by lying on them badly during sleep, but the cable held up to more than six months of rough use and I didnt notice any damage until I broke the pins is that the right word? off the cable so I would think that you just were unlucky.