Tanktalus, thank you for your reply.

As stated my Bitcard account uses the same email address I used to post to p5p. When multiple people are involved in a thread and I reply to one of them, it doesn't get posted to the list until after moderation, so rather than time travel or people responding to post I've made without my mail being displayed. Perhaps I didn't explain that as well as I should.

I have asked perl5-porters-help@perl.org to clarify my suspicion that membership (even digest) negates the moderation step. I'll also raise the question with the Bitcard admins. Once I have confirmation either way I'll update the thread. Thanks again.