I am 1099 and paid taxes for 2018 after filing; both payments to state and federal have been returned to me via paper checks in the mail. Should I be concerned?

Did you make any estimated payments during the year that you didn't enter on 1040 Line 17?  That sounds really odd for both federal and state.  Did you mail checks for the tax due and maybe they also took it directly out of your bank account?

Thanks for responding! I did make estimated payments during the year but I listed them all on my return. I filed my taxes and still owed $1478 to Fed and $699 to state. I paid both electronically and have received 2 checks for those exact amounts. No explanations so far. The state check came in April, only a few days after I paid and the federal one just showed up today.