You have multiple values in the same cell. Check your aggregation, perhaps put Measure Names to the columns (if you have measure values in the text pill) or post a screenshot of your entire tableau workscreen/attach your workbook so it's clearer what's happening.
Actually the issue appears to have corrected itself since I opened the workbook. In the mean time I have upgraded to 9.3 and rebooted the PC so all those factors might be the reason the text is legible now. Thanks for responding