In de.fraunhofer.aisec.cpg.frontends.java.DeclarationHandler::242:

// TODO: can field have more than one variable?

The answer is yes :)
Multi-variable declarations are wrapped in a DeclarationStatement, but statements only live inside of methods, so I guess multi-field declarations should be mapped to multiple independent FieldDeclarations. However, the most important thing is that the field declaration appears in the target RecordDeclaration.

Example:

public class Point {
    int x, y;
    ...
}

results in RecordDeclaration with only one field x.
Any access to y will be mapped to a placeholder field declaration.