Good morning. I also bought a fenix 5 and I'm having the same problem with the rust on one of the connections so I sent it back to Garmin in Spain were I Ihave purchased it and it's been 10 days and no reply and it's a lot of money for watch that is a month old that's starting to rust. I also have another Garmin vivoactiveHR and GPS in my car which I have had now nearly three years with no problems at all. What solution does Garmin have with this problem as I really like this watch.
Hope to hear from you soon
Regards
Diego