correct spelling of last name is "Moilanen" - not sure if there is another way to have this updated.
The 1950 U.S. Census index is fully user-correctable on FamilySearch.
On the page where you took the screenshot, click the "page" icon at the left of the name you want to correct. On the resulting index detail page (https://www.familysearch.org/ark:/61903/1:1:6X1J-J6QF), click the "Edit" button in the middle of the black stripe at the top. This will take you to the new "edit [nearly] everything" tool, where you can correct the surname, add or correct relationships, and generally fix almost anything that's wrong in the index.
Search for Arthur Mailanea born 1906. You should see an "EDIT" button, click that and follow the instructions.