[psacawa]

It happens all the time for software that is copyleft-licensed in projects that are unwilling to also adopt a copyleft license. For example, it blocks linking the node interpreter to libreadline [0]. On the other hand, cpython is also permissively licensed, yet it does link to the same library, so who knows what the legality of linking against a GPL lib really is.

[0] https://github.com/nodejs/node/issues/5608

[josephcsible]

This isn't quite the kind of conflict I meant, since the licenses are compatible and the maintainer just doesn't want to do it.