ORA-31011 on XMLTYPE column - oracle

Question

I'm using Oracle version - 11.2.0.4
I've reproduced the problem I'm facing in a more simplified manner below.
I've 2 tables with XMLTYPE column.
Table 1 (base_table in my example below) has storage model for XMLTYPE as BINARY XML.
Table 2 (my_tab) has storage model for XMLTYPE as CLOB.
With the XML in base_table I'm extracting the value of an attribute based on certain condition. This attribute in turn is a name of a node in xml contained in my_tab and I want to extract that node's value from my_tab.
Please note that I do not have the liberty to change this logic at the moment.
Code was working fine till the storage model for XMLTYPE column was CLOB in both tables. Recently base_table was recreated (drop and create), so it's storage model got modified as BINARY XML as I understand that's the default storage model in version 11.2.0.4
Here is create table stmt and sample data -
create table base_table(xml xmltype);
create table my_tab(xml xmltype)
xmltype column "XML" store as clob;
insert into base_table(xml)
values (xmltype('<ROOT>
<ELEMENT NAME="NODEA">
<NODE1>A-Node1</NODE1>
<NODE2>A-Node2</NODE2>
</ELEMENT>
<ELEMENT NAME="NODEB">
<NODE1>B-Node1</NODE1>
<NODE2>B-Node2</NODE2>
</ELEMENT>
<ELEMENT NAME="NODEC">
<NODE1>C-Node1</NODE1>
<NODE2>C-Node2</NODE2>
</ELEMENT>
</ROOT>')
);
insert into my_tab(xml)
values (xmltype('<TEST_XML>
<SOME_NODE>
<XYZ>
<NODEB>My area of concern</NODEB>
<OTHER_NODE> Something irrelevant </OTHER_NODE>
</XYZ>
</SOME_NODE>
<SOME_OTHER_NODE>
<ABC> Some value for this node </ABC>
</SOME_OTHER_NODE>
</TEST_XML>')
);
Below query fails:
select extract(t.xml, sd.tag_name).getstringval()
from (select '//' || extract(value(d), '//#NAME').getstringval() || '/text()' as tag_name
from base_table b,
table(xmlsequence(extract(b.xml, '//ROOT/ELEMENT'))) d
where extract(value(d), '//NODE2/text()').getstringval() = 'B-Node2') sd,
my_tab t;
ORA-31011: XML parsing failed
ORA-19202: Error occurred in XML processing
LPX-00601: Invalid token in: '///text()'
However, this query works fine and is able to extract the value of node I'm interested in. It can be seen that tag_name is fetched as required, but when it is used within "extract", it's value is somehow lost.
select sd.tag_name, extract(t.xml, '//NodeB/text()').getstringval()
from (select '//' || extract(value(d), '//#NAME').getstringval() || '/text()' as tag_name
from base_table b,
table(xmlsequence(extract(b.xml, '//ROOT/ELEMENT'))) d
where extract(value(d), '//NODE2/text()').getstringval() = 'B-Node2') sd,
my_tab t;
If I change XMLTYPE storage model of base_table back to CLOB, the erroneous query works fine again.
I would like to understand what's going wrong with storage model as BINARY XML.
I modified query as below, which is working fine. i.e. convert to clob and back to XMLTYPE:
select extract(t.xml, sd.tag_name).getstringval()
from (select '//' || extract(value(d), '//#NAME').getstringval() || '/text()' as tag_name
from base_table b,
table(xmlsequence(extract(XMLTYPE(b.xml.getclobval()), '//ROOT/ELEMENT'))) d
where extract(value(d), '//NODE2/text()').getstringval() = 'B-Node2') sd,
my_tab t;
Thanks,
Kailash