>Or was an update pushed by Mozilla, that we are not aware of?
It affects all Firefox versions, even ESR, so the suspicion is that an external service updated (at exactly 12AM PST).
Bug 1749910 Comment 42 Edit History
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>Or was an update pushed by Mozilla, that we are not aware of?
It affects all Firefox versions, even ESR, so the suspicion is that an external service updated (at exactly 12AM PST), specifically one that may load balance for our telemetry/update/blocklist servers.