Aha! Roadmaps | "Filter by status" displays duplicate statuses on ideas portal
If you have multiple workspaces linked to one ideas portal, you might notice that an idea status shows up twice on one idea.
This is likely because your different workspaces use a different ideas workflow, but within those custom workflows, some of the statuses are named the same. Your ideas portal assumes that different workflows have different statuses, so it displays both statuses.
There are two possible solutions to this.
If all the workspaces linked to your ideas portal are the same workspace type, then use the same workflow for the ideas record type across those workspaces. Your portal will then display only one set of statuses.
If the workspaces linked to your ideas portal are different types, they cannot share the same workflow. In this case, you should name the statuses in each workflow so that they have unique names. Your portal will then display the statuses for each workflow, but will not display them as duplicate statuses.