Either too much or not enough sunlight causes some succulents to turn purple, and judging by the growth pattern and lighter colour of the leaves, it seems like it doesn’t get enough sunlight. It being so focused in those areas where leaves are attached would probably indicate it’s trying to heal up some wounds, and trying to protect it from sunlight.

As to why it’s dropping seemingly healthy leaves, I have a theory. If I see this correctly, the roots are popping out everywhere, indicating that it has nowhere to go. This will slow down growth and it will drop older leaves in order to sustain the growth.

That’s just a theory though. Personally, I would repot it into a bigger (plastic) pot with drainage, and place it somewhere that gets a bit more sunlight and track how it’s growing.

Would also appreciate a higher res picture to definitely say it’s the roots and maybe check out the specks on the leaves, as that could be a disease.