after so-openstack completes creation of vf-module in openstack, heatbridge raises exception

2020-04-10T11:32:35.682Z|370032ee-8e23-4a67-b606-545d404ca6e3|org.onap.so.heatbridge.HeatBridgeImpl - Successfully authenticated with keystone for tenant: 087050388b204c73a3e418dd2c1fe30b a
nd region: RegionOne
2020-04-10T11:32:35.895Z|370032ee-8e23-4a67-b606-545d404ca6e3|org.onap.so.heatbridge.HeatBridgeImpl - 3 heat stack resources are extracted for stack: 2ae8fbd6-36e7-4917-89d9-a6c2c363fc9f
2020-04-10T11:32:36.327Z|370032ee-8e23-4a67-b606-545d404ca6e3|org.onap.so.adapters.vnf.MsoVnfAdapterImpl - Heatbrige failed for stackId: RegionOne_ONAP-NF_20200410T113039889Z_vdns_Expansion
_001/2ae8fbd6-36e7-4917-89d9-a6c2c363fc9f
java.lang.NullPointerException: null
at org.onap.so.heatbridge.HeatBridgeImpl.getPserverMapping(HeatBridgeImpl.java:298)
at org.onap.so.heatbridge.HeatBridgeImpl.createPserversAndPinterfacesIfNotPresentInAai(HeatBridgeImpl.java:281)
at org.onap.so.adapters.vnf.MsoVnfAdapterImpl.heatbridge(MsoVnfAdapterImpl.java:466)
at org.onap.so.adapters.vnf.MsoVnfAdapterImpl.createVfModule(MsoVnfAdapterImpl.java:1133)
at org.onap.so.adapters.vnf.MsoVnfAdapterImpl$$FastClassBySpringCGLIB$$8b1f101c.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:295)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688)
at org.onap.so.adapters.vnf.MsoVnfAdapterImpl$$EnhancerBySpringCGLIB$$420fa91.createVfModule(<generated>)
at org.onap.so.adapters.tasks.orchestration.StackService.createVfModule(StackService.java:147)
at org.onap.so.adapters.tasks.orchestration.StackService.executeExternalTask(StackService.java:88)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.handleExternalTask(TopicSubscriptionManager.java:151)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.lambda$acquire$0(TopicSubscriptionManager.java:107)
at java.util.Arrays$ArrayList.forEach(Arrays.java:3880)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.acquire(TopicSubscriptionManager.java:102)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.run(TopicSubscriptionManager.java:86)
at java.lang.Thread.run(Thread.java:748)
2020-04-10T11:32:36.362Z|370032ee-8e23-4a67-b606-545d404ca6e3|o.o.so.adapters.tasks.orchestration.StackService - The External Task Id: f78d9e20-7b1e-11ea-af17-da7fb2842252 Successful
2020-04-10T11:32:36.423Z|370032ee-8e23-4a67-b606-545d404ca6e3|o.onap.so.adapters.tasks.orchestration.PollService - Executing External Task Poll Service for Create Vf Module