Probably Raviola was invented because it was better sounding to American ears, better for commerce. Later on, with ethnic cultures considered hip, the Italian word Ravioli became more favored. Just wonder.
The OxED has these uses of ravioli which predate the OP's references:
1760 C. Hervey Let. 27 Oct. in Lett. from Portugal, Spain, Italy & Germany (1785) II. 439 Our food consisted in some macaroni, raw ham, boiled beef, or bouilli, and..a dish of ravioli, or cheese made into a pudding.
1839 Countess of Blessington Idler in Italy II. 16 Here the polenta , polpetta , and ravioli , the three favorite dishes of Genoa, are prepared.
1841 Thackeray in Fraser's Mag. June 721/2 For the same money, I might have had..A heap of macaroni, or ravioli.
1898 L. Merrick Actor-Manager 66 Oliphant was duly introduced to ravioli.
It has no instances of raviola. Could someone in Reno have initially misspelled it; that misspelling being copied until someone noticed and corrected it; then others following the correction?
As a very young child in the 1950s I first learned raviola, by imitation, not my own invention. Whether this was at home, at school, or elsewhere I have no recollection. I do remember having to teach myself to say ravioli later. It was later still that I taught myself to ignore everyone else and be happy as a nonconformist.
Edit: This was in central New York State.
I wonder if the spelling/pronunciation of ravioli/raviola has any relation to the well known, bifurcated pronunciation of MissourEE/MissourAH.