Adding companies (one by one) does not detect whether a company is already part of a project. The company is listed only once in the project page but double counted in the company tab.
See Milenium Copthorne Hotels in
https://wikirate.org/Research_Page?rp%5Bcompany%5D=Millennium+Copthorne+Hotels&rp%5Bmetric%5D=Business+%26+Human+Rights+Resource+Centre%2BModern+Slavery+Statement&rp%5Bproject%5D=University_of_Nottingham_Modern_Slavery_Act_Research_2020&rp%5Byear%5D=2019
I've been working on this project page, the example above is not there anymore. Instead see "Samsonite_Limited" within the same project page: https://wikirate.org/University_of_Nottingham_Modern_Slavery_Act_Research_2020
I've made a PT story for this. Fwiw, we've never made any rule that lists must be unique, so from a tech perspective this isn't a bug so much as a missing feature (though clearly one we want). Point is: no problem reproducing it :)
What is the desired behavior? If you submit duplicates do we raise an error? Or do we only keep the first instance? Or...
At the moment the duplicated company is displayed just once in the project page, but it is counted twice.
Desired: The company that is already part of the project does not show as a "suggested company name" and cannot be added (error messages explaining the company is already part of the project). It would also help if the list of already added companies is displayed alphabetically.