I got really fast response from Resilio Support. Many thanks!
This will solve the problem: add line "enable_placeholders": false to myconfig.json file (any place, in first level json), for example:
{
"device_name": "My Headless Mac",
"storage_path" : "/Users/resiliosync/Library/Application Support/Resilio Sync/",
"use_gui" : false,
"enable_placeholders": false,
"use_upnp" : true,
"webui" :
{
"listen" : "0.0.0.0:8888",
"login" : "admin",
"password" : "password"
}
}
Note the commas to preserve json syntax. Restart Sync (reboot) .