All PMs I've had since we moved to Huddler have been like this. I do use Hotmail, though I don't think that would make a difference.
Get a PM from someone.
Check your email. Both the subject line and their avatar (in the email) will have their username as lowercase, despite how it's shown on the site.
Example, from user BWG:
The name should be all uppercase/correctly formatted.
I don't believe my browser or set up should matter here. I've already posted a few bugs on Huddler making everything lowercase, so it's definitely not on my end. ;)
Your email notification.