Line 432 of $VIMRUNTIME/syntax/vim.vim

 syn match  vimSynMtchOpt   contained   "\<cchar="  nextgroup=VimSynMtchCchar

To be consistent with the rest of the labels used, the leading V should be 
lowercase.

In Context:

" Syntax: match {{{2
syn 
cluster vimSynMtchGroup contains=vimMtchComment,vimSynContains,vimSynError,vimSy
nMtchOpt,vimSynNextgroup,vimSynRegPat,vimNotation
syn keyword vimSynType  contained   match   skipwhite nextgroup=vimSynMatchRegion
syn region  vimSynMatchRegion   contained keepend   matchgroup=vimGroupName 
start="\k\+" matchgroup=vimSep end="|\|$" contains=@vimSynMtchGroup
syn 
match   vimSynMtchOpt   contained   "\<\(conceal\|transparent\|contained\|excludenl\|s
kipempty\|skipwhite\|display\|extend\|skipnl\|fold\)\>"
if has("conceal")
 syn match  vimSynMtchOpt   contained   "\<cchar="  nextgroup=VimSynMtchCchar
 syn match  vimSynMtchCchar contained   "\S"
endif