Fermentation finished or not?

I recently brewed a Belgian tripel. The OG was 1.072 and I pitched 2L of yeast (5 gal). The yeast went nuts in the primary for at least 10 days--had to use a blow off tube. I transferred to a secondary after two weeks. It's now been in the secondary for two weeks, all quiet the whole time and I thought the fermentation was done. I was planning to bottle, but some activity has started again! Not a lot, just a few bubbles in the airlock and some yeast on top. What to do, bottle or wait?

Thanks for any help....

Take gravity readings. If the same for 3 days bottle. Always better to wait longer than needed than to jump ahead.

What type of yeast did you use and what temp? Paradingbull has some great advice dont want to rack off too soon!

I used Wyeast 3787, two packs and grew them both up in 2L starter. I can take a gravity measurement and see where it's at. Just seems odd that it seemed to be done and now is taking off again so I am hoping nothing bad is happening.

That yeast is famous for taking a long time to finish up. It can rip through the first 95% of fermentation and then take a long time to get the last few points down. So I would recommend making sure it is done before you bottle. I learned that the hard way one of the first times I used that yeast. I thought it was done and bottled. I ended up ith way overcarbed beer. Not bottle bombs or gushers, but definitely more carb than the amount of sugar should have produced.

The other explanation is that it is just a pressure difference. Is this one done yet?

Thank you so much for the advice, really helpful!