Sort key lookup on a project is not returning the options we expect

Sort keys are fields used to hold a variety of different custom data and so the lookup will be returning a specific set of data depending on what has been set up.
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To resolve this issue Support will need to investigate the lookup and possibly the database view it gets it's data from. Therefore please raise a new case and reference the title of this article and please include details of the sort key lookup and the the options appearing and the others expected.