Yes, I do, but I don't think they're wrong in this case. Charles III is king over England. That is title is not normally phrased as such may be irrelevant, since it can be phrased that way and still be accurate.
Is it wrong, though? I don't think either of us know. There are thousands of sources that call Charles III the King of England. Legal precedent may say it doesn't matter if that's his official title, but it only matters how he is known. If someone named "Michael Jackson, King of Pop" in a document, it probably wouldn't be invalid just because there's no official, legal status to be King of Pop, but Michael Jackson was well known as that. Charles III is well known to be the King of England, erroneously or not, and that may matter more to the court than his official legal title.
The question is, when it comes to this legal title, what matters more? The legal title, or being able to correctly identify the person named? I suspect that being able to correctly identify the person named is the only important part when it comes to this law, since his status as king probably makes no difference to the law.