Your repeater is likely actually in router mode.
Change it to bridging / AP / whatever so that your main router provides the IP addresses, if possible.
Did you check that the mac address of your phone is not changed if you are connected to the repeater ?.. Some repeaters are changing the first 6 characters of the mac address (by having the 6 first characters of the repeater mac address instead) and keeping the last 6 of your phone… So in this case, you create a group with the two device_trackers which should be home if one of the two device_trackers is “home”…