Corner indicator light question.

1973 Fury III: When my headlights are on, my driver’s side corner indicator has been staying on solid. It used to flicker on sometimes but usually stayed off. Now that it’s been staying on, I’m beginning to question if it’s supposed to be on constantly when my headlights are on along with the passenger side or if it is designed to be off and only illuminated when the turn signal is on like it has been.