in my experience using Celigo, if there was a way to fix that which is questionable, you want to try running that flow dynamic mode maybe

how do i do that?

in the celigo field mapper, you type "Use Dynamic Mode" on the right/netsuite side, and on the left side type "true" with the quotes. this can require you to have to map other fields though, and may mess up other mappings though so id def recommend opening a case with them. basically the mode treats the record creation more as if it were being created in the UI