As requested, here are the request/response logs:
AdsClientLibs.SoapXmlLogs Information: 1 :
-----------------BEGIN API CALL---------------------
Request
-------
POST /api/adwords/cm/v201601/CampaignCriterionService
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; MS Web Services Client Protocol 4.0.30319.34209)
Authorization: ******
Content-Type: text/xml; charset=utf-8
SOAPAction: ""
Content-Length: 1164
Accept-Encoding: gzip
Connection: Keep-Alive
TimeStamp: Tue, 09 Feb 2016 08:42:55 GMT
Response
--------
Content-Encoding:
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
Content-Length: 473
Cache-Control: private, max-age=0
Content-Type: text/xml; charset=UTF-8
Date: Tue, 09 Feb 2016 06:42:39 GMT
Expires: Tue, 09 Feb 2016 06:42:39 GMT
Server: GSE
TimeStamp: Tue, 09 Feb 2016 08:42:55 GMT
<soap:Envelope xmlns:soap="
http://schemas.xmlsoap.org/soap/envelope/"><soap:Header><ResponseHeader xmlns="
https://adwords.google.com/api/adwords/cm/v201601"><requestId>00052b509fa23c880ac4da02d9000217</requestId><serviceName>CampaignCriterionService</serviceName><methodName>get</methodName><operations>1</operations><responseTime>227</responseTime></ResponseHeader></soap:Header><soap:Body><getResponse xmlns="
https://adwords.google.com/api/adwords/cm/v201601"><rval><totalNumEntries>2</totalNumEntries><Page.Type>CampaignCriterionPage</Page.Type><entries xmlns:xsi="
http://www.w3.org/2001/XMLSchema-instance" xsi:type="NegativeCampaignCriterion"><campaignId>347371961</campaignId><isNegative>true</isNegative><criterion xsi:type="IpBlock"><id>23078300211</id><type>IP_BLOCK</type><Criterion.Type>IpBlock</Criterion.Type></criterion><CampaignCriterion.Type>NegativeCampaignCriterion</CampaignCriterion.Type></entries><entries xmlns:xsi="
http://www.w3.org/2001/XMLSchema-instance" xsi:type="NegativeCampaignCriterion"><campaignId>347371961</campaignId><isNegative>true</isNegative><criterion xsi:type="IpBlock"><id>42157191244</id><type>IP_BLOCK</type><Criterion.Type>IpBlock</Criterion.Type></criterion><CampaignCriterion.Type>NegativeCampaignCriterion</CampaignCriterion.Type></entries></rval></getResponse></soap:Body></soap:Envelope>
-----------------END API CALL-----------------------