When creating a PSA plot for a project with multiple dynamic phases in the mentioned Plaxis versions, realise that by default in the Output program all dynamic phases are selected. As a result of this default selection of all dynamic phases you will obtain one PSA plot in which all dynamic data is combined. The resulting PSA plot in this case is not correct since it should be based on the data of only one phase.
After creating a PSA plot use the settings window (F3) to select only one dynamic phase and recreate the PSA plot.
Since PLAXIS 2D 2012.01, and since PLAXIS 3D 2013.00, Output will by default only select one dynamic phase.