We've got a document library with over 5000 items. At first we had a lookup column of about 9 options for what essentially was a category for the document.
The client would like to use the modern experience, and when coming to the library, be able to use this filter from the column header. Under 5000 items in the library we see all 9 items in the filter by selection area.
When we go over 5000, only 1 of the selections show in the list, which is odd. The column is indexed as well. Since the original column in question was a lookup column to another list, I tried duplicating the column as just a single line of text and then ran a powershell script to copy the value, thinking that the 5000 limit might have problems with lookup columns, but I get the same issue with my single line of text column (also indexed).
We are talking about 9 possible choices here, it's not a managed metadata item of 150+ some items that I've seen people here talk about. I don't understand why only 1 of the items shows up (even though in the files returned, you see all the different category types represented).
Now I can create views based off the indexed column, but the client wants to be able to use the UI filter by on the column header using the all documents view.
