The table only cares what the portfolio owns now. It uses the current holdings and works back in time to figure the return for the given period. Any trades made by the portfolio are ignored when calculating table returns. The table also always includes dividends in its return calculations.
However the chart does it differently. It considers the actual trading that went on in the period and therefore is a more accurate gauge of return. Also with the chart, whether to include dividends or not is an option under the Chart Settings menu.
Also note the table operates on fixed periods only (e.g. 3 months, 1 year, 2 years), whereas the chart can represent any period.
We expect the chart and the table not to agree when there are trades in a portfolio. The chart is more accurate.
Please note the Dashboard (available with all plans) and Portfolio Analytics (available with Premium and Premium Plus plans) will show portfolio details that account for the trade history.