If that case wasn't cracked before, it took a hard hit somehow. Dropped in the shop? Even if it was cracked, they should have seen it on the pre-service inspection and let you know what they found. That they didn't lends more weight to them doing it out of negligence and trying to cover it up.There is a ridge or lip at the tip of the mouthpiece area that keeps the mouthpiece from sliding off when using a zip tie. Here is another pic....
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