The referee's report states that objects were thrown onto the field at this time and the FA will investigate.
"It has been brought to our attention that objects were thrown on to the pitch, as it is in the referee's report," said an FA spokesman.
Liverpool are expected to receive a warning and will be asked to try to identify the culprits using video footage.
But this latest incident highlights the FA's concern about over-excessive goal celebrations and they are keen to ensure referee's penalise players who provoke opposition fans.