An example is the word "Fulfilment" found on issue workflows despite US English language being the default for the site/user language settings. The UK English standard spelling of the word uses one "L", whereas the US English standard spelling is "Fulfillment" with two "L"'s.

Please audit for and adjust any UK English words being used within the US English language pack for Jira-generated content to assist customers who rely on certain spellings within queries/automations or overall standardization of language. 

Current workaround is to manually edit any affected words if the area they are within provides edit capabilities, the example above being the editing of the issue workflow name itself.