Very mixed experience, but now only positive

I have twice ordered more of these hoses for my city bike.
the first two tubes are in a straight line just burst in my simple journey without that I could find a reason for it. (One in the front and rear, no stones, no punctures, rim tape and valve in order).
I ordered yet a second time because I like to use on all my wheels Continental hoses.
This second shipment is now working for two months without any problems under heavy use (about 30 kilometers per day to and from work). Basically, I recommend these hoses, maybe the fault lay with me.