Field names, whether within single quotes or no single quotes, should be checked that they exist in the source and not silently fail.
Derived a length of a string and used the distribution node output to create a select node to pull out only the short answers. Connected Source node to the Select node (skipping the derive node.) It returns an empty table and the stream runs without error. This outcome usually means that no cases that fit the selection criteria were available. However, in this case, no cases were available because the selection criteria did not represent data that existed in the part of the stream that ran.
Request that rather than returning an empty table, single quotes in Modeler's Expression Builder indicate that the expression should validate against the available fields.
Resolving the problem
Enhancement Request Submitted