Are you referring to a nimatta? Or does "the light" refer to something else? I don't know much about the U Ba Khin system and its terminology, but I remember clearly at the one course I took that the general emphasis was on ignoring any countersigns that arose, or at least not investing too much worth into them. That might change as someone goes deeper, you might want to ask Ben!
Gain and loss, status and disgrace,
censure and praise, pleasure and pain:
these conditions among human beings are inconstant,
impermanent, subject to change.
Knowing this, the wise person, mindful,
ponders these changing conditions.
Desirable things don’t charm the mind,
undesirable ones bring no resistance.
His welcoming and rebelling are scattered,
gone to their end,
do not exist.
- Lokavipatti Sutta