9682c5b created the issue
I've started getting this error when attempting to downloading anything from Amazon S3:
"The specified key does not exist. Please contact your web hosting provider for assistance."
I've confirmed that this started after updating to 7.9.0, and reproduced on multiple machines. Uninstalling and reinstalling 7.8.5 resolves the issue, and I am able to download the same files that were failing with 7.9.0.