There is a duplicate of every activity that I have completed that shows up on the Android and Web Explore.
I contacted Gamin support regarding this issue. After a fair bit of back and forth using the trial/error method, it seems that the issue has been resolved.
I had to remove the watch from the Explore device list and unpair from the phone (Android). After adding the watch back to Explore and Garmin Connect via bluetooth, I would get only one version of the activity as expected.
For full disclosure, I have since removed the Explore app from my phone. I use Basecamp to generate/manipulate tracks and waypoints then copy to my Instinct. When the Explore app would sync after loading tracks from Basecamp to my watch, I'd would end up losing the tracks off the watch that I had just copied from Basecamp. I've tried to use Explore, just not a fan.