I've no idea why.
They showed in in Sunderland North where Labour won more of the vote than last time and the Tories massively lost their share.
The swings are blatantly from Tories to Reform.
Although the last time they showed the " Swing" to the Tories, who won 1% more than Theresa May, whilst the Lib Dems the majority of the national swing away from Labour.