Possible Bug with Exchange 2010 SP3 RU1

I was going through Technet forum and found some administrators are facing issues post installation of RU1. 

Even though there is a 30% improvement in fixing the issues like soft delete, after implementing SP3 RU1 few admins faced the mail delivery issues with the sent mails.

All receive mails and OWA was working fine but the sent emails are going to Poison Queue after the update.

On server there will be several errors:

---> Error 10003 on MSExchangeTransport:The transport process failed during message processing with the following call stack: System.NullReferenceException: Object reference not set to an instance of an object.

   at Microsoft.Exchange.Data.Transport.Email.PureTnefMessage.Microsoft.Exchange.Data.Transport.Email.IBody.GetContentWriteStream(Charset charset)

   at ............

--> Error 4999 on MSExchangeCommon: Watson report about to be sent for process id: 5724, with parameters: E12, c-RTL-AMD64, 14.03.0146.000, edgetransport, unknown, M.E.D.T.E.P.M.E.D.T.E.IBody.GetContentWriteStream, System.NullReferenceException, a79c, unknown.

ErrorReportingEnabled: False

If this is really a bug, MS will release interim update to address the issue. 

Disabling the Transport Rule is a work around not a solution, until Microsoft fix the problem.