Will changes in the components of liquefied gas affect the proper operation of multi-stage pumps?

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In our plant’s alkylation unit, the refrigerant buffer tank (with a pressure of 0.35 MPa) activates a multi-stage pump when there is a high proportion of propane in the mixture, in order to send material to the light hydrocarbon removal tower for the separation of the propane component from the mixture. During the last start-up of the pump in this process, the propane composition was 10% and the isobutane composition was 60%; no further start-up of the pump was required. Six months later, since the propane content in the refrigerant buffer tank reached 50% and the isobutane content reached 30%, it became necessary to start the pump again. After starting the pump, the outlet pressure was 2.1 MPa; once the outlet valve was slightly opened, the pressure began to drop to 1 MPa. Eventually, a sound indicating evacuation was heard, and water condensed due to the low temperature of the pump body (the outlet pressure gauge showed 0.4 MPa when the pump was stopped). Could it be that the excessive amount of propane component is preventing the pump from operating properly? The inlet pipeline has been purged; there is nothing in it, and the inlet filter was opened for inspection – it is also clean. I also hope an expert can explain it