List type fields should not be available in 'Additional group by' on reports as they are not available in 'Group by' - Known Error

List type fields should not be available in 'Additional group by' on reports as they are not available in 'Group by' Description List type fields are not available in fields to Group by on a report or list menu. The group by and additional group by select list and slush bucket dont contain the same number or type of fields that can be selected because the slushbucket is a different type of UI element that can not be easily manipulated or updated to show on the fields that are supported in the report designer.

Steps to Reproduce

1. Create a new report using classic or New UI and select Task table. Note that in list of fields on 'Group by' there is no 'Additional assignee list' field available.

2. Click the '+' icon to open additional group by and add 'Additional Assignee list'. Even if grouping by a list type is supported, it is not consistently available on group by and additional group by choices.

Workaround After carefully considering the severity and frequency of the issue, and the cost and risk of attempting a fix, it has been decided to not address this issue in any current or near future releases. We do not make this decision lightly, and we apologise for any inconvenience.

The workaround is to only use fields shown in the main group by select list. Any additional field types shown in the additional group by slushbucket are not supported.