Can special characters like `#` or `&` cause an 'href syntax error unrecognized expression' if not handled properly?

Yes, if special characters like `#` (for anchors) or `&` (for query parameters) are not part of a valid URL structure or are used incorrectly within the `href` attribute, they can lead to syntax errors. For example, an unescaped `&` within a URL might be misinterpreted by some parsers. However, these are generally less common causes of the 'unrecognized expression' error compared to fundamental syntax issues like missing quotes or invalid protocols.