WSDL contains duplicated schema elements on subsequent WSDL requests

Onlu first request after deployment for WSDL returns valid XML document. Subsequent requests will return WSDL with schema elements duplicated as many time as many request has been made for the WSDL. For example third request for WSDL will return somethink like this:

<?xml version="1.0" encoding="UTF-8"?>
<wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:ns1="http://exception.xml.meddra.dss.roche.com" xmlns:soap11="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soap12="http://www.w3.org/2003/05/soap-envelope" xmlns:soapenc11="http://schemas.xmlsoap.org/soap/encoding/" xmlns:soapenc12="http://www.w3.org/2003/05/soap-encoding" xmlns:tns="http://www.roche.com/drugsafety" xmlns:wsdlsoap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.roche.com/drugsafety">
<wsdl:types>
<xsd:schema targetNamespace="http://www.roche.com/drugsafety" elementFormDefault="qualified" attributeFormDefault="qualified">

[...]

<xsd:element name="searchResponse">
<xsd:complexType>
<xsd:sequence>
<xsd:element ref="tns:dictionary" minOccurs="1" maxOccurs="1" />
</xsd:sequence>
</xsd:complexType>
</xsd:element>

[...]

<xsd:element name="searchResponse">
<xsd:complexType>
<xsd:sequence>
<xsd:element ref="tns:dictionary" minOccurs="1" maxOccurs="1" />
</xsd:sequence>
</xsd:complexType>
</xsd:element>

[...]

<xsd:element name="searchResponse">
<xsd:complexType>
<xsd:sequence>
<xsd:element ref="tns:dictionary" minOccurs="1" maxOccurs="1" />
</xsd:sequence>
</xsd:complexType>
</xsd:element>

[...]

This does not stop WebService to handle SOAP erquest properly.