SO
SittingOvation
I imagine that, quite simply, someone 'didn't press the button'. Exactly the same thing happened with Midlands Today once. We got the generic clock and UK Today 18:00 headlines, but MT was back to normal from 18:15 onwards.
On a separate occasion, everything was okay until 18:29 (or whatever) - we got Midlands clock and MT 18:00 and 18:15 headlines. But at 18:30ish we got generic balloon with apologetic announcement, and UK Today started. UK Today presenter had introduced herself and way partway through reading first haedline when we cut to MT. MT presenters were also partway through reading headlines, so they hadn't been late starting, they just hadn't gone on air (presumably thay didn't know this). So, as I said at the start, SOMEONE 'DIDN'T PRESS THE BUTTON'!
On a separate occasion, everything was okay until 18:29 (or whatever) - we got Midlands clock and MT 18:00 and 18:15 headlines. But at 18:30ish we got generic balloon with apologetic announcement, and UK Today started. UK Today presenter had introduced herself and way partway through reading first haedline when we cut to MT. MT presenters were also partway through reading headlines, so they hadn't been late starting, they just hadn't gone on air (presumably thay didn't know this). So, as I said at the start, SOMEONE 'DIDN'T PRESS THE BUTTON'!