Grouping does not take effect in chart

Hi! I am using MES reports and wanted to convert them to reporting version 7.8.

I am currently trying to convert the OEE Report.

I already followed the instructions in … rts#p53836

I am successful in replicating the report, however, when it comes to the timeseries chart, it combines the graph for Lines 1 and 2, where in each chart should have 1 line only.

For my table, I already added Line in grouping. and I placed the chart inside Line details.
Please help me to figure out what seems to be the problem.

Thanks in advance.