Still don't think it's the insert, the hole is in line with the valve and has fairly sharp edges. I rode with just a tube today and no puncture yet.
What pressure were you running?
The marking/pattern on the tube around the hole and along the tube also look unusual, as if it was so low it was rubbing against the rim tape.
@psg1ben started
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Still don't think it's the insert, the hole is in line with the valve and has fairly sharp edges. I rode with just a tube today and no puncture yet.