Here is my personal views:
I dont think its a glitch. I believe they remove your option to change the address at the time your file is open by VO. They might send you request for documents or PP. If you change the address at this time, the VO may have not seen the new address.
Once the VO is done with file and close it with new BFD, you again get the address and option to change it. Now, if the address change is requested by applicant, this raises a flag and the file is immediately sent to VO or someone to change the address and do whatever need to be done.
I strongly belive this is the reason why the address appears and disappears whenever you see notes on file or someone have your file open at CHC.