These are tread separations. Happens quite often with Chinese ST tires. They don't need punctures. They don't need to be hopped over curbs. They need better construction methods and/or materials. It seems many try to make excuses, or rationalize why they do NOT last. It is just that they are not up to the task.
I have had several tires go down like that. Never jumped a curb. And two of them had the tread wrapped around the suspension. And yes...I looked closely at them. No punctures. Just the ends of the treads that have come apart. And off they go. The tires have not gone flat until later. On one tire, it never did go flat. And still had 80# of air. But still the tread was off it. And yes...that was a second gen Chinese Marathon. LRE ST.