Is this a bug in Daffodil?

[Costello, Roger L.]

Hello DFDL community,

My (binary) input is this:

[cid:image003.png@01D54B82.A9F5AF20]
Parsing the input with this DFDL schema:

<xs:element name="input">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="Section_1" type="Section_1_type"
                minOccurs="0" maxOccurs="unbounded"
                dfdl:occursCountKind="implicit"/>
            <xs:element name="Section_2" type="Section_2_type"
                minOccurs="0" maxOccurs="unbounded"
                dfdl:occursCountKind="implicit"/>
            <xs:element name="Section_3" type="Section_3_type"
                minOccurs="0" maxOccurs="unbounded"
                dfdl:occursCountKind="implicit"/>
            <xs:sequence dfdl:hiddenGroupRef="padToByteBoundary" />
        </xs:sequence>
    </xs:complexType>
</xs:element>

produces this XML:

<input>
  <Section_1>
    <code>1</code>
    <three-bits>3</three-bits>
    <one-bit>1</one-bit>
  </Section_1>
  <Section_1>
    <code>1</code>
    <three-bits>3</three-bits>
    <one-bit>1</one-bit>
  </Section_1>
</input>

If I remove maxOccurs="unbounded" on Section_3, then I get this warning message:

[warning] Schema Definition Warning: Section_3 is an optional element or a 
variable-occurrence array and its alignment (1) is not the same as group[4]'s 
alignment (8).

There is only one xs:group in my DFDL schema, so the warning message is clearly 
wrong.

Despite the warning message, I get the same XML output.

This seems like a bug in Daffodil. Yes?

Below is my complete DFDL schema.  /Roger

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";
    xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/";>

    <xs:include schemaLocation="default-dfdl-properties/defaults.dfdl.xsd" />
    <xs:include schemaLocation="unsignedint-types.dfdl.xsd" />

    <xs:annotation>
        <xs:appinfo source="http://www.ogf.org/dfdl/";>
            <dfdl:format ref="default-dfdl-properties" />
        </xs:appinfo>
    </xs:annotation>

    <xs:element name="input">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="Section_1" type="Section_1_type" 
minOccurs="0" maxOccurs="unbounded" dfdl:occursCountKind="implicit"/>
                <xs:element name="Section_2" type="Section_2_type" 
minOccurs="0" maxOccurs="unbounded" dfdl:occursCountKind="implicit"/>
                <xs:element name="Section_3" type="Section_3_type" 
minOccurs="0" maxOccurs="unbounded" dfdl:occursCountKind="implicit"/>
                <xs:sequence dfdl:hiddenGroupRef="padToByteBoundary" />
            </xs:sequence>
        </xs:complexType>
    </xs:element>

    <xs:complexType name="Section_1_type">
        <xs:sequence>
            <xs:element name="code" type="unsignedint2">
                <xs:annotation>
                    <xs:appinfo source="http://www.ogf.org/dfdl/";>
                        <dfdl:assert test="{. eq 1}" />
                    </xs:appinfo>
                </xs:annotation>
            </xs:element>
            <xs:element name="three-bits" type="unsignedint3" />
            <xs:element name="one-bit" type="unsignedint1" />
        </xs:sequence>
    </xs:complexType>

    <xs:complexType name="Section_2_type">
        <xs:sequence>
            <xs:element name="code" type="unsignedint2">
                <xs:annotation>
                    <xs:appinfo source="http://www.ogf.org/dfdl/";>
                        <dfdl:assert test="{. eq 2}" />
                    </xs:appinfo>
                </xs:annotation>
            </xs:element>
            <xs:element name="four-bits" type="unsignedint4" />
            <xs:element name="two-bits" type="unsignedint2" />
        </xs:sequence>
    </xs:complexType>

    <xs:complexType name="Section_3_type">
        <xs:sequence>
            <xs:element name="code" type="unsignedint2">
                <xs:annotation>
                    <xs:appinfo source="http://www.ogf.org/dfdl/";>
                        <dfdl:assert test="{. eq 3}" />
                    </xs:appinfo>
                </xs:annotation>
            </xs:element>
            <xs:element name="four-bits" type="unsignedint4" />
            <xs:element name="five-bits" type="unsignedint5" />
        </xs:sequence>
    </xs:complexType>

    <xs:group name="padToByteBoundary">
        <xs:sequence dfdl:alignment="8" dfdl:alignmentUnits="bits" 
dfdl:fillByte="%#r00;"/>
    </xs:group>

</xs:schema>