I've also seen this issue, but it started after I paired a second phone with the car. When I took initial delivery only my phone was paired. It was rock solid for 3 to 4 days. Once my wife paired her phone my phone would no longer automatically connect. Yesterday I did a device forget, re-added, and it still wouldn't connect. What ultimately got it to connect was holding the VOL + >>> keys. That will reboot your SYNC. I know because my SYNC3 has had issue for a year on my F150 and I have reboot frequently.
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