Licensing in different areas can make for amazingly complex software problems. I was a programmer for a mutual fund holding company till I retired and we sold shares in all 50 states and a LOT of different countries. Each fund had it's charter which gave lots of rules for what could be sold and what stock it could hold. Each state and each country and each state in some countries had similar rules.
We wrote all our software in-house and we were a leader in the industry in automation. But we didn't dare write the software that decided what stock we could buy or where we could sell shares. The company hired this out to another company that had expertise in this sort of thing and they did a good job for us. I was in charge of monitoring what they did and I was always happy I didn't have to write that mish-mosh.
The only other software we didn't write in house was word processors. This was in the days before the internet was a big thing and we had a mainframe with terminal emulators on PC's. I even wrote the terminal emulators. We were very self sufficient. But we left the licencing software to experts.
I suspect the complexity of what Amazon is facing with this is even greater than what we were dealing with. It's not surprising things go wrong sometimes.
Barry