What I suggested to explain that use is that there is a trend among certain groups of speakers to regularize language forms.
For example:
If the second person singular, present, indicative of verbs ends in “-as, -es” >> Quieres, Piensas, etc… then speakers extend that rule to other tenses like preterite. For example: quisiste >> quisistes.

The same happens with “alguien/nadien” (as presented by Jordan)

Many hispanics I have met over the years who have immigrated to the US to work in factories think that you say ‘nadien’ instead of ‘nadie’ because if ‘alguien’ ends with an ‘n’, why wouldn’t the opposite?

The reasoning makes sense similar to with the present and preterit indicative. Descriptively, the communication occurred, the symbol was conveyed adequately to the hearer. But prescriptively, it’s incorrect.

The same phenomenon happens in Buenos Aires.
It is true that this occurrence does not appear in learning books, neither are they taught as correct in school. True that it is attributed to people with no formal education.
However, language is a complex entity. It is not only a linguistic phenomenon but also a social one: it´s a membership mark used by the members of a certain group to show they belong to it.
As I see it, analyzing it in terms of native Spanish/learned Spanish or correct/incorrect would be to remain on the surface of the problem while -unconsciously- stigmatizing not a linguistic form, but the linguistic community who speaks it.