Apostrophe ' being added to duration column after using the form


Hello, I have a form that I occasionally use to enter data into my sheet. Every time I enter data it adds an apostrophe before my duration text causing it not to populate a finish date. For example, instead of carrying 3d (3 days) from the form, it carries it over as '3d. I've replaced the form with another and it continues to do the same thing. Any ideas on things I could check to fix this issue?