A few days ago I sent a tab from Firefox on my phone to my desktop. Since then, every time Firefox syncs the tab opens up in the background. I tried sending another tab, and now both tabs appear when Firefox syncs. I tried creating a new profile and signed in. When I sent a tab from my phone to the new profile, the same behavior occurs. Reproduction steps: 1. Sign-in to Firefox (release version) on Android and Nightly on desktop. 2. Send a tab from Firefox on Android to Nightly on Windows. 3. Tab appears every time Nightly syncs.

This is happening to me as well; sending tabs from iOS to Nightly on my iMac is resulting in the tab opening again and again and again. Over a dozen times already today, and it's only been an hour or so since I sent them. Today is the first time it's happened to me though (although I may have been using an older Nightly until late last night).

I am experiencing the same issue. Mark, I emailed you my Sync log.

We are tracking this in bug 1262021