Rubber nipple on intake keeps blowing off

Hello,

I have had the same problem probably three times. Basically what happens is there's a rubber nipple on the intake right near the firewall and it keeps blowing off resulting in loss of coolant completely (broken down and had to be towed). I had the newly designed intake put in about three months ago (the one that's metal up front near the thermostat). I was driving from Detroit to Peoria, Illinois and all of a sudden the car starts smoking under the hood. Got it towed to the nearest auto shop. And I think this is where the problem kind of started. The rubber nipple was dry rotted. So the mechanic replaced it, tightened it down, filled my coolant, and off I went(this was 2 months ago). BUT. Just yesterday, I stepped on the gas and heard a pop under the hood. And I knew it was that rubber nipple. Same thing happened. Anti freeze everywhere. Got it towed to my mechanic who is amazing. He looked at the intake and said the person who replaced that nipple used some sort of prying device. Probly a flat head screwdriver just to get it on there and take my money. My mechanic pointed out exactly what had happened and the picture probably speaks for itself. Does that look like someone pried in there because it's metal and it's torn down the middle which is why it probably gave way and blew. Under normal circumstances, would that kind of crack happen? I would think it would stay round and the cap would just blow? I'm just afraid it's going to happen again. Hopefully not