SQL timeout expired on CRM 2011 when Plugin is fired(Inconsistent behavior)

We are getting SQL Timeout Expired error when we try to create, Share/Unshare an Account record. It is an Inconsistent Behavior

Plugins are registered on these operations. Could you please help me to understand WHY and WHEN it occurs. Much appreciate if you could provide a solution.

Error:

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: SQL timeout expired.Detail: 
<OrganizationServiceFault xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/xrm/2011/Contracts">
  <ErrorCode>-2147204783</ErrorCode>
  <ErrorDetails xmlns:d2p1="http://schemas.datacontract.org/2004/07/System.Collections.Generic" />
  <Message>SQL timeout expired.</Message>
  <Timestamp>2013-05-31T15:38:28.5643531Z</Timestamp>
  <InnerFault i:nil="true" />
  <TraceText i:nil="true" />
</OrganizationServiceFault>

Screenshot:

Thanks,

Madhu M.