Numbers in Spanish are pronounced different than they should be.
I've heard ochentitrés in Chile, instead of ochenta y tres.
In México diciséis, dicisiete, diciocho, dicinueve instead of dieciséis, diecisiete, dieciocho, diecinueve
Yep, and most other words, too. It's like Americans never pronouncing the "g" on the ends of words ending in "ing", or never pronouncing the first "r" in February.
In Caribbean Spanish (Cuba, Puerto Rico, Venezuela, etc.) they leave the "s" off the ends of words, gloss over the "d" in between vowels, and they run words together. "Mas o menos" becomes "maomeno" and "helado" becomes "hela'o".
In Argentina they pronounce "ll" like a Portuguese "j" (Rio de Janeiro), while in parts of Spain it's pronounced like the "llia" sound in the English name "William"- Caballo = cabayo, cabazho, cabalyo, depending on where you are.
These are just differences in pronunciations you have to get used to from area to area. English sounds different in Glasgow, London, Brooklyn, and Texas.
Of course not only the numbers but also the other words can be different in different countries , that's the most normal thing... For example in Mexico : camión also means Bus other than lorry
Pero en los números se trata de vicios del lenguaje... errores en la dicción.