Number (double) and does not comply with its supposed superclass Number (integer)

I am running into the Number (double) and does not comply with its supposed superclass Number (integer) issue while executing a GroupBy node. I am using KNIME 3.2.0. I appreciate if someone can give me some tips on resolving this issue.

ERROR GroupBy              0:434:234  Execute failed: Runtime class of object "2970.0" (index 8) in row "Row0" is Number (double) and does not comply with its supposed superclass Number (integer)

Attached document provides details on the data types of hte fields used.

• knime_error.pdf