What I found
The chart is a claim accuracy reading. It shows the share of checked claims about each supplier that were right and the share that were incorrect and the share that could not be checked.
Three facts account for most of the errors and they are the current standard tariff and whether a supplier installs heat pumps and which companies a supplier has absorbed. Every model got the ownership history of at least one supplier wrong.
I traced the incorrect answers to the pages the models cited. Most came from comparison sites and from news articles older than a year. The suppliers' own pages were rarely cited for the facts that were wrong.
What incorrect AI answers mean for a company
A fact that is wrong in an AI answer is usually wrong on a page the company does not own. Fixing the company's own page is necessary but it is not enough. The sources the models draw on have to carry the fix too and that is a plan rather than an edit.
This is one reading and so it is an observation. It becomes a finding when the next reading repeats it. My details are on the contact page if you have checked the same facts and found something different.