BSL and GPL code are probably never mixing since they prohibit each other. This creates friction in GPL world and tends to produce incidents line this [1] out of thin air.
Sure, but the issue that you link is different. The "problem" there is that Debian (and many others) only distribute software that complies with the open source definition of freedom, which Crockford's license and the BSL runs afoul of as they both discriminate against uses. So, this is about what some are willing to distribute, not license compatibility.
BSL and GPL code are probably never mixing since they prohibit each other. This creates friction in GPL world and tends to produce incidents line this [1] out of thin air.
1. https://github.com/jshint/jshint/issues/1234