unfortunately I have a crash report for BRouter, you will find it in the attachment along with the profile to reproduce the issue.
Commandline is also in the logfile.
I only happens with java-9-openjdk for me, openjdk 8 works fine, I am no expert, but it might also be a bug in openjdk.
I am using v1.4.10 from your website.
Hopefully you can find out what causes it.
Thank you for checking!
Jakob