DataTable row group and sortable columns are not working together

[nndnha]

CodeSandbox Case
https://codesandbox.io/s/sleepy-leaf-2krq2?file=/src/DataTableRowGroupDemo.vue

Current behavior
When sorting is activated, the rows are no more grouped.

Expected behavior
When sorting by columns, the grouped rows must be retain.

[zsuzsmuzs]

Same issue for primevue 2.4.x

[djoldman]

I ran into this as well.

I've played with adding fields that combine the group field with the field you want to sort. This requires casting everything to a string. But this approach fails with reverse sorting ( we want the group field to sort non-reverse while reversing the sorting field).

I wonder if a hard coded sortMode="multiple" would be the best solution at the moment?