`char-syntax` reports a different syntax than `describe-char`, breaking some functionalities

[agreselin]

Something in the syntax setup (use of syntax properties? I don't know much about this matter) causes (char-syntax (char-after)) to return a different class than describe-char or (syntax-class-to-char (syntax-class (syntax-after (point)))) for some characters, e.g. # and ". This fools forward-same-syntax (it gets stuck at # or quotes), electric-quote-local-mode and electric-pair-mode (the electric-pair-inhibit-predicate and electric-pair-text-syntax-table don’t work as expected).