Doubled fields in an exploration chart due to their pre-selection

[adann_CB_96]

Hi, in of my apps I am using a chart exploration to let a user create an own report from the scratch. Some fields are already selected as the default fields and it generates duplicates:

As You can see, one field is pre-selected and the same field is a bit below as a normal field waiting for a manual user's selection.

When the field is also selected by a user, it gets double even in the report:

Is there any chance to fix it? I would be grateful for any help.

[SterreKapteijns]

I have not experienced this before using Chart Exploration. Maybe create a case with Support. Is the particular field just a dimension or does it contain a set expression?