Thanks Josh,
I think we ran into the same issue, when using a My Token as the link. Do you know if/where this is addressed in the docs anywhere? I'm surprised I have never heard about that. I'd love to understand the issue deeper so we can insure we don't run into this in the future.
Jill, this is a longstanding rule. There's nothing really deep about it: because of order-of-operations, Marketo needs to see the link as an offsite href before looking at the token value itself.
Another rule exists for Velocity tokens, where the token cannot be tracked if entered as http://{{my.token}} but rather the fully-formed <a> tag must be output from the token.
We have some docs describing how to set it up here Using URLs in My Tokens - Marketo Docs - Product Docs . The email parser needs http/https outside of the token in order to know to build the token before decorating all the links with tracking parameters.