Steps to repro:

1. Create a new custom field of type user picker
2. Create an issue, and populate a value into this field
3. Create a new rapid board
4. Add the custom field from step 1 to the People section of the Issue Details

Expected:

Mouseover on the custom field, and Assignee, and Reporter should all provide the limited user profile.

Actual:

User profile only comes up for the custom field. Mouseover for Assignee and Reporter is broken.