julia-vim syntax highlighting is incompatible with rainbow parenthesis/brackets:
https://github.com/luochen1990/rainbow
rainbow is compatible with the syntax highlighting that comes with vim for other languages but
with julia-vim within function blocks it reverts to usual julia-vim highlighting.
Others have this problem with a related rainbow parenthesis/brackets plugin:
https://discourse.julialang.org/t/julia-vim-and-rainbow-brackets/57180