I have same multiselect option many time this happens when I imported Airtable base to Seatable through script.
The options are like this:
And when I use group by the that it shows separate groups for that.
But when I manually correct it and make only one option for same option in multiple select and manually corrected them.
Then also it is showing same groups like earlier.
I am unable to share more than one screenshot that will try to share in comment.