Solution
This error is thrown when you use this VI to extract a data type that isn't included in the variant you are inputting. See the below VI. It is trying to extract a Boolean from a variant. While there is a Boolean within the input, it's packaged inside a cluster data type, which needs to be the data extracted from the variant, before extracting the Boolean.

Figure 2: Incorrect Variant to Data Usage
The correct way to extract the Boolean from this code is shown below:

Figure 3: Correct Variant to Data Usage