Comment 1 for bug 259019

The "quoted" color highlighting is controlled by the quote_regexp option. This option defines the pattern that's considered a quoted line, and defaults to "^([ \t]*[|>:}#])+", which means a line starting with any amount of whitespace followed by any of these characters: |>:}#

If you want to ignore # as a possible quote character, then set quote_regexp to "^([ \t]*[|>:}])+", which will fix this particular instance. Without trying to make mutt intelligent, I'm not sure how it could tell the difference between a line that *is* a quote, and one that looks *just like* a quote. :)