I shared a tab from Fennec to Desktop the other day and I continue to get this tab opened again and again, every couple of hours on my desktop browser. I'm running latest nightly on Desktop 48.0a1 (2016-04-04) and Play Store release on Android. Maybe related: The shared link is a 404. Apologies if that's not the correct component, it's hard to locate where to file these bugs.

Thanks for the report! You've found the right component. :-) This is a regression introduced in bug 1250531. Bug 1262021 will have the fix; that should land today. If it's OK with you, I'll close this out as a duplicate.