How To Fix W8353 - Operator '&1' cannot be applied to a multiline element

SAP Error Message - Details

• Message type: E = Error

• Message class: W8 - Workflow: Expressions, data flow

• Message number: 353

• Message text: Operator '&1' cannot be applied to a multiline element

What causes this issue?

The existence operators 'EX' and 'NX' cannot be applied to a multiline
element, also when this multiline element only contains object
references.
Please note: The operators 'EX' and 'NX' are also not suitable for
checking the availability of a container element at runtime. They only
check whether an object reference that is already available in the
container refers to an official object available.

Error message extract from SAP system. Copyright SAP SE.