Definition which? Let's take a look at the relevant one from the OED. 1.1 That is of concern, that gives cause for consideration; important, weighty. arch. N

Definition which? Let's take a look at the relevant one from the OED. 1.1 That is of concern, that gives cause for consideration; important, weighty. arch. Note the annotation 'archaic' - as in, not actually in current use. Words do, indeed, have multiple meanings. They do also have common usage and this one is just silly and bad writing. 'Concerning' does not mean 'cause for concern' - if you are sure of the contrary, find me a non-blithe usage of it, in that sense, in any current publication that is not a forum post or blog.