Grammatical hypercorrection

I heard an interesting hypercorrection this afternoon.  A public television reporter for the PBS Newshour was commenting on the issue of military rape and referred to members of the armed services being “courts-martialed.”

In English, when a two word noun-phrase is in the form <noun-adjective> (the so-called “post-positive adjective” form) the plural is often of the form <plural noun-adjective>, e.g

• attorney general – attorneys general
• battle royal – battles royal
• court martial – courts martial
• forest primeval – forests primeval
• Knight Templar – Knights Templar
• Pound Sterling – Pounds Sterling
• professor emeritus – professors emeritus

etc.

Now, in this case, the reporter must have been eager to show off that she knew the plural of “court martial” is “courts martial” and not “court martials.” 

However, when noun is “verbed,” we generally usually take the singular form of the noun, not the plural noun.  Thus, a noun is “verbed” but it is not not “verbsed.”   People are “impacted” and not “impactsed.”   Books, even when written by multiple people are “authored” and not “authorsed.”

So, “courts martialed” is certainly wrong – an awkward overcorrection that probably sounds incorrect to most native English speakers (although a Google search reveals that this particular hypercorrection has been made by many).  How do such things get by editors?