Suddenly on July 15 or 16, 2019, my amazon mobile ads Fill Rate in Japan tanked from 100% on both Android and iOS to ~15% and it has not recovered in over 6 weeks. Did something change in Japanese law that I missed, or with Amazon's support of Japan as an advertising region or within Amazon's SDK? I still have the same # of requests coming in, a relatively healthy >25k per day on Android making the data relatively stable and honest. I made no changes to my app nor to my advertising accounts or mediation stacks. Indeed, this just seems to have "happened" on its own. Has Amazon's pool of ads in Japan dried up?
EDIT: Or is Amazon changing tactics and chasing higher eCPMs in Japan? Is this longterm? Should I make changes to my mediation settings? Any insights would be great! :)
Is anyone else seeing this too or is it just me?