Mr. Sk. Looks to me that the soldered edge has given up the ghost. From picture #2, it looks like the end cap is still attached (bottom most piece against your thumb) then the rubber gasket, THEN the thicker piece that should have stayed on the HE. That thicker piece should be soldered to the HE and failure of that solder joint is the cause of the blow-out. Absolutely no evidence of solder so this is NOT new development. Best suggestion I can make is take off the HE and either do it yourself or have the cap soldered back on. Not sure if OEM was soft (lead) or hard (silver type) solder.