No, you can get unanticipated yaw in a helicopter without loss of effectiveness, it just means you don't have enough pedal applied.
If a gust of wind hits you and the heading changes, the TR hasn't lost effectiveness.
If it was LTE you wouldn't be able to correct it.
But loss of effectiveness does not exist. There is no unanticipated yaw you are unable to correct as long as you keep your RPM. LTE was only used as a synonym of unanticipated yaw (#45)
extract from AC 90-95
I am not an english speaker but I understand from that extract of AC 90-95 that "unaticipated yaw" and "LTE" are two ways to designate the same phenomenon.