I've been getting 503 SLOW DOWN errors when posting using presigned URLs to s3. Specifically, I generate ~10 presigned URLs in my backend, pass them to the client, and upload 10 images using those presigned URLs.
On Chrome or Firefox, these POST requests all load fine. On Safari, some number of POST requests between 2 and 5 will work, and then I will hit 503 SLOW DOWNs.
I've tried this with many different types of images (jpg, png) of many different sizes (10kb all the way to 1mb) on a few different macs, and I get consistent behavior. Also, I'm almost definitely not hitting the s3 prefix post quota limit, since we're talking about O(10) images.
I'm stumped for how to even debug this. Any help appreciated!
