Some User Picker elements in Request Forms, lose the selected user if the selected user has multiple first or last names with the names separated by spaces. You'll be able to pick the user from the form but the value gets lost passing to the Change Request. The problem only becomes evident with users such as Smith, Mary Ann or Del Toro, Juan, and when the value configured to be picked up in the User Picker form element is Full Name. This error does not occur if the user picker is setup for setting a different value from the selected user such as user ID or email address, instead of full name.
This problem has been fixed in RSA Identity Governance & Lifecycle as of versions 6.9.1 P19, 7.0.0 P06, 7.0.1 P02 and beyond. Upgrading to the latest patch will resolve this issue.
Another option is to change the User Picker element to use something other than Full Name as a value. Other options are ID, Unique ID, User ID or Email Address. If you need the full name, you'll need to upgrade.