Runnable Jars not working after obfuscation

[jgeramb]

Hello, I have got a runnable jar file, but after obfuscation it does not work any more :/

[jgeramb]

This is the error code when starting the jar: https://pastebin.com/fjEZq6nm

I am using the version 1.71

[superblaubeere27]

I've never seen this kind of bug befure. Can you please give me some additional information? And please give me the configuration

[jgeramb]

Ok i have updated to 1.9.1 and there is still the same issue.

[jgeramb]

But when I toggle "Bad concat" off it works! Please fix that and thank you for your nice support!