No, it is not "common" per se, but a missing original signature letter for an e-filed return (typically IRS Letter 12Cor 3531) usually means your digital signature, the PIN or prior-year AGI you entered, failed to properly authenticate or didn't attach to the data packet sent to the IRS. The IRS has your tax data, but without a valid signature, the return is not legally "filed," which stops your refund from being issued.
An original signature in this context means they need you to physically sign a paper declaration (often a provided form or a copy of your 1040) with a pen and mail or fax it back to them. Once they receive this physical confirmation that you are indeed the one who filed the return, they can finish processing your return.
