The quickest way I can think of is to use Unbundle Function. When you wire the cluster to it, the Unbundle function will display the data type for each element. You'll just need to look through these names and see which elements do not match.
If you make one cluster an indicator, and use Bundle function to wire each cluster element, you will then see the coercion dot on the mismatching element.
Please see the attached example that has DBL and SGL cluster elements.
Zvezdana S.
National Instruments