Unexpected Secondart Fermentation Question

Anyone had fermentation pop back up in the secondary (no fruit or additional additives added, just racked from primary to clear) that went on slow but steady for several days? I had an Irish Red that I did last year, so no real changes this time around, however that day I had planned to bottle it (it was about 3 weeks old) it all of a sudden started to get bubbles to the surface and then start to exit out the airlock once every few seconds and has been for a week now. Now the gravity before I noticed it was 1.016 which was in the recipe TG variance (1.010 - 1.016). I left it alone for another week and it is still bubbling slightly but now has a gravity of 1.010. If it is the same tomorrow it should be safe for bottle - curious if anyone else has had that happen. First time for me but I think it might have had something to do with some of the crazy temp changes and weather we had around that time before the temp got right around back to normal. Thoughts?

If the beer was 1.016 when you racked and now is1.010, it wasn't done fermenting when you racked so you moved it too early.

+1 That's the most likely thing. It wasn't quite done when you racked it off the yeast cake and it took a little time to get going again. Wait for it to stabilize.

An infection could also do this, but you'd probably notice other signs.

I've had secondary happen because the dog was wagging his tail, hitting the carboy. The yeast woke back up and the airlock started singing again, kept it up for days.

The faster the yeast sinks (British yeast usually = high flocculation), the more likely that it wasn't quite done eating when it sank. By knocking it around, you brought some yeast back into suspension, where it found more sugar. Not that rare. I usually perturb a dry cider once a day for the first few days to a week before it really takes off. It doesn't take much.