liquibase-core/src/main/java/liquibase/database/core/PostgresDatabase.java
@Override
    public String escapeObjectName(String objectName, Class<? extends DatabaseObject> objectType) {
        if ((quotingStrategy == ObjectQuotingStrategy.LEGACY) && hasMixedCase(objectName)) {
            return "\"" + objectName + "\"";
        } else if (objectType != null && LiquibaseColumn.class.isAssignableFrom(objectType)) {
            return (objectName != null && !objectName.isEmpty()) ? objectName.trim() : objectName;
        }

        return super.escapeObjectName(objectName, objectType);
    }
@Override
    public String escapeObjectName(String objectName, Class<? extends DatabaseObject> objectType) {
        if ((quotingStrategy == ObjectQuotingStrategy.LEGACY) && hasMixedCase(objectName)) {
            return "\"" + objectName + "\"";
        } else if (objectType != null && LiquibaseColumn.class.isAssignableFrom(objectType)) {
            return (objectName != null && !objectName.isEmpty()) ? objectName.trim() : objectName;
        }

        return super.escapeObjectName(objectName, objectType);
    }
This has special case logic to handle NOT quoting column names if they are
of type 'LiquibaseColumn' - columns in the DATABASECHANGELOG or DATABASECHANGELOGLOCK
tables.