The custodian's reporting on the 2018 Form 5498-SA is correct and proper. The fact that you made an excess contribution or had any amount distributed in 2019 has no effect on what the custodian was required to report on the 2018 Form 5498-SA.
How was the contribution made, though your employer and reported with code W in box 12 of your W-2, or by you personally? This affects how things get reported.
