There's a lot of panic here and on Nuna's facebook page. I've got 2 of these seats, and am obviously concerned having seen the video. However we must put it into perspective. Every car seat on the market will have passed the minimum tests required, so Nuna is quite correct to point out that this one does too, and is therefore considered safe. What I didn't appreciate when I bought the seat was just how low those standards are. The i-Size regulation does exceed the previous regulation as the speed is higher, but it's still only around 35mph. Not many seats have had this ADAC testing conducted, so there's nothing to say that many other car seats may also fail. We may be jumping from the frying pan into the flames!
I really like the swivel function of the Nuna Rebl, it's helped me so many times especially as I'm now pregnant and still having to lift my 14.5kg toddler into the seat when he's not playing ball. I do wonder whether it's this swivel function which has resulted in a weak point, meaning that it fails in this manner.
I do believe this seat is as safe as any other seat on the market. I will be keeping my toddler rear facing in it rather than turning forward facing as this is still safer.
Some retailers have been authorised to exchange for a different brand, or wait for the new "improved" Nuna Rebl in January. They don't know how it's different though yet. Unfortunately we bought from Mothercare which haven't been authorised (yet?).
I don't know what we will do moving forward, we need to weigh up the swivel function against seats which have passed this ADAC test of which there are very few. There is also the Swedish Plus Test, which would rule out the swivel function as well as no forward facing-able seats pass this test.