Is eCommerce Order ID unique?

[gonerator]

Hi! In one dataset I was analysing, I encountered 2 records of Order ID with the same Order ID. I was always under impression that tracker won’t accept second Order with the same ID, but I tested that I can send order with the same Order ID again. Should it be the case?

[gonerator]

Okay, nothing to see here I think, it looked like that in the debugger (and still does), but processed into session log there is only one order - the first one. Also there is only one in raw data. So I’m really not sure how it might have been in the other dataset