The same happened to my DUT-3. I think the break was a bit cleaner on mine. Due to the remaining splinters, it's very easy to trace the bridge in pencil. You'll see exactly where to glue it.
Mine was only six weeks old and Donner offered to replace it. I declined and got a full refund (and they didn't even want me to return it). I was going to cannibalise it later on.
My father-in-law said he'd fix it, and he did so when we took it over during a visit. I thought he had a special clamp or two, and maybe hot hide glue. However, he removed loose splinters and then applied superglue (Locktite). He only needed to hold the bridge in place for about 30 seconds, just manually. The glue left some traces on the top, so I would suggest to cover the top (whatever glue you use).
It's been over two years, and I haven't experienced any problems. I know it's a cheap uke, but I absolutely love it!
So, if it's still under warranty, reach out and they may offer to send a replacement.