I work in recruitment and these mistakes are in CV's (yes you can use an apostrophe there) from all over - Tech folk, Marketing and MBA's alike. There are some genuinely tricky ones - the possessive of a noun ending in an s e.g. the idea belongs to a Scandinavian airline = SAS's idea or SAS' idea ? I know the theory but acceptable in common international English usage? I don't know
When a CV has one or two of the errors mentioned, we encourage people to fix them. When theres

a handful, we often reject the CV, especially if the client has specified attention to detail as a selection criteria!
And is there ever a time to use its' apart from the possessive for Mr and Mrs Its? Tricky thing, English...