I have added an image field "avatar" to the user template. The field settings are "Maximum files: 1", "Formatted value: Single items (null if empty)".
So I believe I should be able to get the URL of this image in my template with
But this returns
If I add the avatar field to any other template besides the User template I can get the URL as expected.
For the user template if I use
I get the URL okay.