It is always possible that you ancestor lived, at least for a time, in a place that seems to make no sense, fits no migration patterns, etc. I still haven't figured out my an uncle was in Arkansas for a few years in the 1910s. There may be a reason, but even so, in his family this is unusual. Anyone who left Illinois either went west or north. South was rare.
Never discount the possibility that a relative in the "wrong" place cannot be yours.