Ask HN: Why does YouTube now trim channel URLs?

For example, go to https://www.youtube.com/c/MichelvanBiezen

It will be trimmed to https://www.youtube.com/c

Then if you do refresh, bookmark it or reopen last closed tab, it gives an error.

The same is for URLs of type user: https://www.youtube.com/user/professorleonard57

This is in both Opera and Firefox.