The panel falls apart. Reduce the edge pressure on soft woods. With hard woods, increase the glue application if needed. Check the moisture content of the stock. OR excessive moisture, causing the glue to be forced out by steam pressure.
Panel shows open joints at one or both ends.
Check on the stock preparation and its lineality within the press. If needed, relocate the stock to obtain uniform pressure on its full length. Stock should be glued as soon after machining as possible. Too much time between machining and gluing. Panel shows evidence of steaming or burning.