Help to verify father on birth record Hetland 1859

I want to tie up some loose ends in my family history and this is one of them. I found this birth record for "Olaus", born Hetland 29 March1859. [https://urn.digitalarkivet.no/URN:NBN:no-a1450-kb20070619610083.jpg] It says the parents were Ole Hansen and Marie Siverdatter from Finnestad but on Finnestad Ole Hansen was married to Marthe Rasmusdatter and they were the parents of Ole Olsen who was actually married to (Berthe) Marie Siverdatter in March 1859. She used her second name as she had a living sister also called Berthe. Marthe Rasmusdatter was too old to be the mother by that time - 61 years old. It looks like Marthe was one of the witnesses. There is another entry for the death of "Olaus" on 29 September 1863, 4 and a half years old and it gives the father as Ole Olsen from Finnestad. [https://urn.digitalarkivet.no/URN:NBN:no-a1450-kb20051208040822.jpg] There were no other families on Finnestad with the same names at that time. I think that "Olaus" is the same child in both entries. Can any one help to explain the differences in father, please! Is it a mistake, an illegitimate birth or something else? Thank you! Karen.