I have a UI rule for field value limitation shown below:
When a value has changed where Closure code (*) equals Cancelled Limit Status to Under Review (Limit field value range) Status equals Under Review;
In testing we discovered that this is inconsistant - sometimes it will limit the status to Under Review and other times it will limit the status to nothing - when you click the arrow next to status there is just a blank line - I tried moving the arrown down to see if it was just a graphical bug with no luck.
Do the inconsistencies occur with different users? If so, are you using status ranges in roles.
Another thing to check is what state does the status Under Review have? If it is closed and the status is on a chnage, if you have workorders still open and the change has the option "Wait for WO completion" set to yes, no closed state status will be offered.