New Task changes reflecting in old Completed Tasks

[Rick Sample]

I just noticed something strange in completed WFs. 
 
I moved some changes for some tasks up to production.  
I removed a field from the display. 
When I look at the old (like a year old) task, I do not see 
the fields that used to be in the tasks. 
 
Looks like all the old tasks have the old data, but the screen changes 
reflect the current layout. And, when I look at the containers, the 
elements that have been removed from display at all capitalized. 
 
Is this a feature or bug?
Oss note?
 
4.6c
 
Rick Sample
Workflow Developer
Graybar, Inc.