I have had my share of adventures with URL parsers and their differences in the past. The current state of my research on the topic of (failed) URL interoperability remains available in this GitHub document.
There is still no common or standard URL syntax format in sight. A string that you think looks like a URL passed to one URL parser might be considered fine, but passed to a second parser it might be rejected or get interpreted differently. I believe the state of URLs in the wild has never before been this poor.
If you parse a URL with parser A and make conclusions about the URL based on that, and then pass the exact same URL to parser B and it draws different conclusions and properties from that, it opens up not only for strange behaviors but in some cases for downright security vulnerabilities.
This is easily done when you for example use two different libraries, frameworks or libraries that need to work on that URL, but the repercussions are not always easy to see at once.