When the bypass isn't 100%

Just found out that my sister's bypass, which was done a few years ago, was only 80% bypassed.  In other words, 20% of her stomach had never been closed.  She didn't lose much weight after surgery.  Of course, her doctor blamed her and said she wasn't following the rules.  She's recently had bad reflux and underwent a procedure, by a different doctor,  this morning when the discovery was made.  
Anyone else have this problem??