source:

Tokenizer.prototype._stateInNamedEntity = function(c){
        if(c === ";"){
                this._parseNamedEntityStrict();
                if(this._sectionStart + 1 < this._index && !this._xmlMode){
                        this._parseLegacyEntity();
                }
                this._state = this._baseState;
        } else if((c < "a" || c > "z") && (c < "A" || c > "Z") && (c < "0" || c > "9")){
                if(this._xmlMode);
                else if(this._sectionStart + 1 === this._index);
                else if(this._baseState !== TEXT){ 
                        if( c !== "="){
                                this._parseNamedEntityStrict();  // this is a bug line.
                       }
                } else {
                        this._parseLegacyEntity();
                }
                this._state = this._baseState;
                this._index--;
        }
};

htmlparser2#Tokenizer.prototype._stateInNamedEntity bug