I just encountered the same issue days ago.
It does not work if we add the changeset into changelog.xml file using the format below:
<include file="path/to/sqlfile" />
To work around, I use another format:
<changeSet author="authour_name" id="your_id">
<sqlFile path="path/to/sqlfile" splitStatements="false"/>
</changeSet>
Here is the link which gives a brief explanation to Problem with dollar-quoted-in-postgresql.