Expression evaluation error at function a!recordActionField, Cannot compare incompatible operands of type Null and type Boolean.

I'm getting the error

Expression evaluation error at function a!recordActionField [line xxx]: Cannot compare incompatible operands of type Null and type Boolean.

I'm not sure why this is occurring.

Code:

 a!gridColumn(
              value: a!defaultValue(
                value: ri!recordActions,
                default: a!recordActionField(
                  actions: {
                    a!recordActionItem(
                      action: relatedAction1,
                      identifier: fv!identifier
                    ),
                    a!recordActionItem(
                      action: relatedAction2,
                      identifier: fv!identifier
                    ),
                    a!recordActionItem(
                      action: relatedAction3,
                      identifier: fv!identifier
                    ),
                    a!recordActionItem(
                      action: relatedAction4,
                      identifier: fv!identifier
                    )
                  },
                  style: "MENU",
                  openActionsIn: "SAME_TAB"
                )
              ),
              showWhen: a!defaultValue(ri!showGridActions, true())
            )