In this edit (https://en.wikipedia.org/w/index.php?title=Philip_Bourne&diff=700560196&oldid=700492602), BG19bot removed |language=English from several cs1 templates. At one time, [[Module:Citation/CS1]] added such templates to Category:CS1 maint: Unrecognized language so that |language=English could be easily discovered and removed. But, the module no longer adds |language=English to the category. Instead, the it accepts the parameter but does not render the language portion of the citation. This was done to aid the translation project at WP:MED for whom the parameter has value. There is no need to continue removing |language=English (or |language=en)
I believe that his is a general fixes issue (I never run AWB with general fixes turned on so can't say for sure). I do not know what version of AWB BG19bot is using.