Exception in changegroup.oberon when using hooks

I'm testing issues service and POST webhook with my repo. If one of those is enabled, every push ends up with following error message:

{{

{\\ ...\\ remote: bb/acl: Uninen is allowed. accepted payload.\\ remote: error: changegroup.oberon hook raised an exception:\\ 'ascii' codec can't decode byte 0xc3 in position 7: ordinal not in range(128)\\ }}

}