Hey @leonhitchens
Welcome from Twitter!
So, I can't see any obvious issues with the setup, so my guess is either this is a bug, or by (unintentional) design.
I'm going to flag this post for Zapier Community Staff to look at. They might have some insight on this issue that I don't, or if required, they can escalate this to the support team for you.
Hi @leonhitchens, thanks for bringing this to our attention. I see that Samantha from Support was able to respond to your email ticket. It's a bummer that it's not an existing request, but I'm glad we're able to log it and put it on our wish list for you.
Thanks @AndrewJDavison_Luhhu for the help on this one!
@AndrewJDavison_Luhhu I checked and it seems like it's not possible to specify the attachment name due to the Trello API doesn't yet have the add a name field yet.
That said, it looks like the ability to set the file name has been suggested so we added Leon's request to our wish list for this.