Okay, got it. There was an odd break at around the twenty minute mark. We received the countdown video, without a countdown clock, and then went back to Kate. But it wasn't identified as the start of a new bulletin, at least for us watching on World.
Breaks like this are normal on the News Channel here in the UK when they're joining a simulcast with BBC One. The countdown without the clock is used to fill the gap while they're waiting for BBC One to join them, so on this occasion News Channel would have been showing the same filler.
They don't usually introduce it as a new bulletin other than the usual "This is BBC News" line from the presenter before the headlines. BBC One does their own introduction before joining the news, News Channel treats it as a continuation of their rolling news programming.
Maybe because the Ten started a minute or so after 22:00 I'm not sure how World could fill a few seconds? Which is probably why they went with pre recorded material.
This may have been the case, but it doesn't sound quite right. News Channel would have also had a gap to fill waiting for BBC One to join, and I'd be surprised if News Channel didn't take the bulletin. I think the usual procedure for News Channel at least is to air extra promos and make use of the looping countdown without the clock, as mentioned above. I would have imagined World News would be similar, so my guess would be something else was going on. I may be wrong though.