EDIT: I've noticed this only occurs when I have
Often, when I connect my iPhone7 to my MacBook Pro 2018 (using a new AppleStore-supplied USB cable), the iPhone prompts "Trust this computer?". I tap "Yes", and then have to enter my six digit pass code on the iPhone.
It's happening more than 50% of the time, probably 60-80% from eyeballing.
i.e. Not every time. It's not 100% repeatable. But I've just tried disconnecting and reconnecting 10 times and 7 times I got this prompt.
This is beginning to infuriate me. Is there any step I can take towards diagnosing?
EDIT: It is worth noting that the cable does work. I am able to transfer data between the computer and phone. So it appears the issue is not related to the cable.