The same Hebrew word עֵינֹת (eynot) is translated 'wells' in Exodus 15:27 but 'fountains' in Numbers 33:9, despite both verses referring to the same location and springs at Elim.

Same category error as the shamayim case: this is ordinary lexical breadth in the Hebrew source meeting ordinary synonym selection in the English target, not a factual contradiction about Elim. עַיִן (ayin; plural עֵינֹת/עֲיָנוֹת) has a broad semantic range covering 'spring,' 'well,' and 'fountain' — the same root that also yields 'eye,' by the natural cross-linguistic metaphor of a spring as 'the eye of the land' (paralleled in cognate Semitic languages such as Arabic ayn). English has no single word that covers this range as tightly as Hebrew ayin does, so 'well,' 'spring,' and 'fountain' are all legitimate, overlapping glosses, and different translators — or the same translation committee working on different books — can reasonably select different English synonyms for the identical Hebrew term without asserting anything different about the referent. Exodus 15:27 and Numbers 33:9 report the same details for Elim (twelve springs, seventy palm trees) using the same Hebrew word; only the English gloss varies.

That Exodus and Numbers independently report identical numerical details for Elim (twelve springs, seventy palm trees) is itself a small but genuine internal-consistency data point — the kind of incidental agreement expected of a real, corroborated itinerary tradition preserved across two books of the Pentateuch.