QStringLiteral iniside a Plugin crashes after the plugin was unloaded

I created a plugin. Inside that plugin there is a function that returnes a QString. Inside of my plugin implementation I created it using QStringLiteral. I store the returned string locally, but never modify it. Later in the program, the plugin gets unloaded, the QString however stays.
As soon as I try to access the string after the plugin was unloaded, the program crashes. This only happens with QStringLiteral, QLatin1String and QString work fine.

I'm sorry I can't provide any code right now, but my project is to complex for easily extract that part. But if neccessary, I guess I could manage something.