When multiple files are imported into a project, it is sometimes possible that the sections are not showing (in the Section view) in the order of the imported files when you are in 'View by Section'. The sections the different files could be jumbled.
This could happen because of which file was imported first or because of section numbering etc.
But this causes confusion (refer ticket 79283). By default, section order should be based on import files, even in 'View by Section' view. It can later be manually reordered if a user wants to.