Answer
Right-click (RMB) that specific column and check its Conditional Formatting settings — that's what's driving the background/text color combination. If the setting doesn't appear in the user's personal profile, it's inherited from the base profile assigned to that user, so you may need to check the base profile instead to find where it's actually configured. The colors can be edited in whichever profile (personal or base) actually holds the conditional formatting setting; the main task is identifying which one that is before making the change.