Snøbjørn Eyvindsson born after the death of his mother Rafertach ingen Cearbhaill.Þjóðhildur Eyvindsdotter born after the death of her mother Rafertach ingen Cearbhaill.Rafertach ingen Cearbhaill is under 12 years old for the birth of her child Helgi "Magri" Eyvindarson.Thorstein "the Red" Olafsson is under 14 years old for his marriage.
In general all dates on these profiles is just fabricated by people who insist on having dates, and it collides when merged by another trees with different estimates.Only when we have died in a known battle of xxx we can give an guesstimate.
I have never seen any dates mentioned in sources for these lines, - they only mention who is the son of who, and the mothers of the children are never mentioned by names, so they are usually fabricated as well.
If it is a problem simply erase the dates and the names of the mothers.