You are correct, the amount the company paid you in 2018 should definitely be on a 2018 Form 1099-MISC, not a 2019 form.
I would recommend that you contact the company regarding this form, they may have used a form for the wrong year and didn't even realize it. They will need to issue you a 2018 1099-MISC and send in a corrected 2019 Form 1099-MISC.
