Scanner fails when an issue is generated with a message containing the NULL character. That can occur when the issue message includes source code:
Making the scanner fail impacts negatively user experience, especially when null characters are supported by compilers (Cobol for instance). The behavior of scanner should be changed by replacing NULL characters \u0000 with the text "[NULL]" (6 characters).
SonarLint should apply the same strategy in order to have a good issue tracking in connected mode (issues are matched using the issue message).