The observation in comment3 seems reasonable to me, Apple uses MSE for that video, but they didn't append any data into the MSE source buffer. This issue is a network issue, move this to another component.
Bug 1919592 Comment 4 Edit History
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The observation in comment3 seems reasonable to me, Apple uses MSE for that video, but they don't append any data into the MSE source buffer, which apparently was blocked by CSP. This issue is a network issue, move this to another component.