Gastric Band Slippage Symptoms

It is important to know that a band can slip (slide) at any time but more commonly several months after the operation and following a period of weight loss. A minor slippage can usually be taken care of by removing fluid from the band, a slip that lasts for a long time or a major slippage that causes severe pain may require a re-operation. One of the firsts smptoms of a slippage is pain or severe reflux even with small portions.

An upper GI study in which a patient drinks liquid and x rays are taken  to see the position of the band and how liquid travels in the esophagus and stomach is a quick but effective test to demonstrate a significant slippage. Over - eating is also another simple cause of reflux that can be treated with portion control.

there are various symptoms that can suggest a band has slipped, while conversely some patients even have minimal or no symptoms ... best thing to do is to evaluate the band, such as with x-ray ('barium swallow') or endoscopy (EGD). but first step if there are any symptoms is to think about deflating the band.  
but from your description it sounds like its just a particular food item that causes symptoms? although its not fun to have to avoid certain things, if the band is evaluated and functioning properly, then perhaps just consider this as an element of food intolerance and things to avoid