The short answer here is yes: it's a coincidence. No serious scholar that I'm aware of has argued that mana was the object of a cultural transfer between the Middle East and the Pacific. The idea that there's a deeper ancestral connection between Oceania and Israel has appeared in Mormon cosmology from time to time and in the writings of various speculative New Age authors, however.

There are two things I'd like to emphasize here. One is that Oceanic mana and Old Testament manna are actually two very different things. As you know, Old Testament manna is a physical thing with a divine origin. Oceania mana, however, is a state. Here's a reference to Roger Keesing's classic essay on this topic and a key quote:

Keesing, Roger M. “Rethining ‘Mana.’” Journal of Anthropological Research 40, no. 1 (Spring 1984): 137–56.

Let me begin by making my claims explicit. Mana, I argue, is in Oceanic languages canonically a stative verb, not a noun: things and human enterprises and efforts are mana. Mana is used as a transitive verb as well: ancestors and gods manaize people and their efforts. Where mana is used as a noun, it is (usually) not as a substantive but as an abstract verbal noun denoting the state or quality of mana-ness (of a thing or act) or being-mana (of a person). Things that are mana are efficacious, potent, successful, true, fulfilled, realized: they "work." Mana-ness is a state of efficacy, success, truth, potency, blessing, luck, realization-an abstract state or quality, not an invisible spiritual substance or medium.

The other thing I'd like to point out is that Oceanic mana does have a fascinating history of cultural transmission within the Pacific. Mana isn't only a Maori concept. It's found in Tikopia, Hawaiian, Mangarevan, Marquesan, Tahitian, Raratongan, Tuamotuan, and quite a number of other languages as well. The definition of the term varies somewhat from culture to culture, but it's pretty clearly the same concept adapted from place to place.