Using CommonSyntax, the following text won't be picked up by the regular parser:
[url=http://example.com]link[/url]
The parser correctly recognize the opening shortcode, continue to getting the parameter value, then finds a /which is a marker token, then look for a closing token, doesn't find it and return false.
Using parameter delimiter like this [url="http://example.com"]link[/url] yields the expected result.