Links in weekly "Recommended in Confluence" e-mails don't work

This only seems to affect users using web-based Zimbra to read e-mails, and does not occur with any other e-mails from Confluence. The problem is also not happening when opening "Recommended in Confluence" emails through another mail clients (e.g. Gmail).

Links in the weekly "Recommended in Confluence" e-mails mostly don't work. Links to people's profiles are fine, but "Continue reading", for example, doesn't do anything (in fact, the "a" tag doesn't have an "href" attribute).

P.S.: I understand that this problem seems to rely on Zimbra's side, however, this doesn't seem to occur with any other e-mails from Confluence. Thus, I'm raising this BUG to check if there's anything strange about the HTML generated by Confluence, perhaps triggering a Zimbra bug.