It appears that when the escapeEscapeCharacter is set to "" (empty string), the final separator (,) in a sequence does not get recognized as such, and the test fails for leftover data.

.......

(debug) 

  data:

       │ (27 to 27)

    450,500

  infoset:

    <tns:e1EmptyEEC xmlns:tns="http://example.com">

      <tns:escapeChar>\</tns:escapeChar>

      <tns:strng>4,000,000</tns:strng>

      <tns:strng>5,000</tns:strng>

      <tns:strng>6,450</tns:strng>

    </tns:e1EmptyEEC>

(debug) 

Left over data: byte 27

UTF-8 text starting at byte 24 is: (450,500)

Data (hex) starting at byte 24 is: (0x3435302C353030)

[Fail] escapeExpressions_03

If i set the escapeEscape character to an arbitrary value (not used in the data), the test passes and all elements parse as expected.

See test_escapeExpressions_03 (failing test), and test_escapeExpressions_01, test_escapeExpressions_01b, test_escapeExpressions_02 for the workaround.

in the following files:
daffodil-test/src/test/scala-debug/edu/illinois/ncsa/daffodil/section07/escapeScheme/TestEscapeSchemeDebug.scala
daffodil-test/src/test/scala/edu/illinois/ncsa/daffodil/section07/escapeScheme/TestEscapeScheme.scala
daffodil-test/src/test/resources/edu/illinois/ncsa/daffodil/section07/escapeScheme/escapeScheme.tdml