Why is FaceTime using the wrong SIM after I installed an eSIM?
With two lines, FaceTime may default to the data eSIM instead of your usual number. Go to Settings → FaceTime and, under 'You can be reached by FaceTime at', select your own number or email; under 'Caller ID' choose your primary number too. That keeps FaceTime using your usual identity even though data runs over the eSIM.
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