ACL key seems to be case-sensitive

[londos]

When setting access control {acl: 'public-read'}, I get an "Access Denied" error. Upper-casing the key {ACL: 'public-read'} fixes the issue, but doesn't seem to be documented.

[TimeLord2010]

This also backed by this stackoverflow question. I was have an error thrown, and changing to upper case solved.

Confunsingly, the exact opposite seems to have been the solution some time ago.