A clue (which brings up a larger riddle), is that the mother--Anna Svensdotter--would later give birth to Johanna Olsdotter on May 4, 1833 (also oäkta), and then shortly thereafter marry soldier Ola Malm. The suspicion is that Ola Malm was the father of Johanna.
The birth record looks like it reads "Suscept. Soldaten Malms ..." but perhaps not.
The riddle is that this Sven never appears with his mother in later HFL. However, we then find a burial record in Konga for an un-named child who died at birth, "Soldaten Ola Malm's son" (https://sok.riksarkivet.se/bildvisning/C0066499_00189). His burial, though, is Nov. 14, 1827, meaning the dates are wrong, or it's a different child. There does not appear to be any child born to Ola Malm in Konga on Nov. 14, 1827, though.