No. Let a mechanical engineer reassure you, an ultrasonic cleaner will not cause an o-ring to fail. You're suggesting the vibrations can somehow deform or compress the o-ring enough to create a gap. This just wouldn't happen, the mass of the o-ring is so small that the force created by vibrating it is miniscule.
Plus, it's compressed in its gland... it's not going to turn to jelly and open up gaps...
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Dude, no. O-rings vibrate all the time. Planes, trains, cars, and, um, water pumps! The o-ring in a water pump creates a seal, not a pump. Come on guys you sound as foolish as the OP.
I really don't know what's up with this board. Yesterday investors who didn't seem to know much posing as experts... now you.
I was only a mechanical engineer for a few years before I moved into business...I agree that it's unlikely to be an o-ring failure, but put your ego away and stop pretending to know more than you do.
You don't know what types of adhesives were used. Some adhesives cure into a brittle substances and break down quickly under vibration.
You don't know the resonate frequencies or vibrational modes of the major watch faces.
You don't know how tightly the ring is compressed or the compression ratio. If it isn't adequate...vibration has a way of acting like a lubricant. It could simply slide out of seal (I've seen something similar happen with old head gaskets).
Remember that these seals were designed to meet the IPX7 standard. They aren't particularly robust. Again, I agree that it likely wasn't water seepage that caused the problem... but lets not pretend we know things we don't.