You might have a faulty watch. I just found out my Instinct is faulty as I had the same issue. They offered a replacement which meant sending it to them, having it sent back etc etc, but I didn't need the explore app really, I found out I can go on connect.garmin.com, create my course there and send it to the watch. Next time I opened the Connect app on my phone it showed the course on my watch. That was good enough for me as I don't really hike in the "wildereness" or somewhere where I would need to do this all the time.
