Hello,
Hrm. On the first glance, this looks like a bug in SourceHook. It looks like reference returns are not supported with manual hooks at the moment.
The reason is that a special class has to be utilized which encapuslates the return type when it's a reference and internally stores it as a pointer. Apparently this is done for normal hooks but not for manual hooks. I hope I just forgot to do it and there's not a bigger problem
I will try to fix this ASAP.
Greetings, PM.