The issue is for me, when I receive e-mail from XDA (and a few other forums) on my Nexus 5 on 4.2.2 using the stock e-mail client, the links to the forum and unsubscribe just appear as text, not links that can be clicked. That's very annoying since it means to click through to a link (like a forum post) I have to copy and paste the link into the browser.
I thought this was a Nexus 5 issue on 4.2.2 but I just bought a new Nexus 7 (2013) and immediately accepted the update to 4.2.2. On XDA again links to forum posts appear as plain text and are not clickable.
I thought it might be something to do with my email provider (1and1.com) but the problem does not occur on any other device I have (I have a Asus Transformer TF700T flashed with CROMi-Xenogenesis nor in Outlook 2010 or 2013.
Plus I changed my e-mail to my Gmail account on XDA and the same problem happens using the stock e-mail client but not using Gmail.
I have gotten around the problem by switching to K9 e-mail but it seems strange that I should get these problems on my two different devices (the only common factor is that they are GED's and are on 4.2.2) and furthermore nobody else seems to have experienced it.