Does the mail server your sending to support and allow DSN? Very few servers these days send DSN. Bounced spam represented almost as much mail as SPAM did. It caused an issue called backscatter.

Better supported is return receipt when the mail is read, but many mail clients offer the return receipt as an option. Thunderbird included. Personally I never allow them. On sending to corporate mail servers you will most likely get the corporate policy. Either required and sent automatically or disallowed completely.

Problem has only occurred since updating Thunderbird. Prior to this everything worked well. Problem occurs on all operating systems and as I use a different mail server at home than at work I'm thinking that TBird is the problem.