Can you point me to a paper or reference to a non-dharmic source where they refer to it their concept, whatever it is, as karma?
In the point-counterpoint jointly done here (#4 in particular) Basics of Hinduism they seem to be two very different concepts.
I believe that this entire argument that karma can be applied to most philosophies is another Baha'i attempt at finding common ground when, in reality, there is none. You've gone ahead and changed the definition of karma to suit this agenda. You change key concepts of many faiths to make it seem like all faiths essentially say the same thing. They don't. It's misrepresentation of all the faiths that came before.
Hinduism and Buddhism while having many similarities also have significant differences as reflected in beliefs regarding both karma and reincarnation.
Buddhism is based on the teachings of Gautama Buddha and they have a recognised body of writings that reflect the Teachings of the Buddha and early Buddhist monks.
Practically all Buddhists believe in the concept of karma whereas only some Buddhists believe reincarnation to mean transmigration of souls. Many Buddhists believe in rebirth rather than reincarnation that is not the same as transmigration of souls. Part of the difference concerns the concept of the soul.
Difference between Hindu & Buddhist Idea of Reincarnation | Difference Between | Difference between Hindu & Buddhist Idea of Reincarnation
According to Takashi Tsuji karma 'is a Sanskrit word from the root "Kri" to do or to make and simply means "action." It operates in the universe as the continuous chain reaction of cause and effect. It is not only confined to causation in the physical sense but also it has moral implications. "A good cause, a good effect; a bad cause a bad effect" is a common saying. In this sense karma is a moral law.'
That sounds very universal to me.
A Basic Buddhism Guide: On Reincarnation