The input multidimensional raster uses a time interval that is not evenly spaced or contains missing intervals. The resulting space-time cube uses these intervals, so care should be taken when using this cube for analysis in tools in the Space Time Pattern Mining toolbox. All time series values in the cube should be evenly spaced and continuous.
No action is required. However, if you intend to perform analysis using the cube, consider altering the time intervals of the multidimensional raster layer to make them evenly spaced.