A method for determining a process anomaly in a fluid flow system, the system having a meter with immersed elements immersed in a fluid of a fluid flow, the method comprising: determining, by the meter and using a data processing circuit, a measured density of the fluid in the fluid flow system; determining, using the data processing circuit, whether the fluid flow system is experiencing a density anomaly based on a relationship between the measured density and an expected density of the fluid in the fluid flow system; determining, using the data processing circuit, a measured phase difference of vibrations of the immersed elements of the meter; determining, using the data processing circuit, whether the fluid flow system is experiencing a phase anomaly based on a relationship between the measured phase difference and a target phase difference of the vibrations of the immersed elements in the fluid flow; and identifying, using the data processing circuit, an anomaly of the fluid flow system based on the determination of whether there is a density anomaly and the determination of whether there is a phase anomaly; wherein the density anomaly is determined to be indicative of a gas entrainment anomaly if the measured density is less than the expected density by at least a threshold density difference; wherein, if the anomaly of the fluid flow system is identified as a gas entrainment anomaly, determining, using the data processing circuit, whether a gas entrainment anomaly identification may be confused with an erosion anomaly identification by determining whether one or more of the fluid and elements entrained in the fluid are likely to erode the immersed elements based on data stored in the data processing circuit; and identifying, using the data processing circuit, that the gas entrainment anomaly identification may be confused with an erosion anomaly if the data processing circuit has data indicating that the one or more of the fluid and elements entrained in the flow fluid are likely to erode the immersed elements. determining, by the meter and using a data processing circuit, a measured density of the fluid in the fluid flow system; determining, using the data processing circuit, whether the fluid flow system is experiencing a density anomaly based on a relationship between the measured density and an expected density of the fluid in the fluid flow system; determining, using the data processing circuit, a measured phase difference of vibrations of the immersed elements of the meter; determining, using the data processing circuit, whether the fluid flow system is experiencing a phase anomaly based on a relationship between the measured phase difference and a target phase difference of the vibrations of the immersed elements in the fluid flow; and identifying, using the data processing circuit, an anomaly of the fluid flow system based on the determination of whether there is a density anomaly and the determination of whether there is a phase anomaly; wherein the density anomaly is determined to be indicative of a gas entrainment anomaly if the measured density is less than the expected density by at least a threshold density difference; wherein, if the anomaly of the fluid flow system is identified as a gas entrainment anomaly, determining, using the data processing circuit, whether a gas entrainment anomaly identification may be confused with an erosion anomaly identification by determining whether one or more of the fluid and elements entrained in the fluid are likely to erode the immersed elements based on data stored in the data processing circuit; and identifying, using the data processing circuit, that the gas entrainment anomaly identification may be confused with an erosion anomaly if the data processing circuit has data indicating that the one or more of the fluid and elements entrained in the flow fluid are likely to erode the immersed elements.