If an eclipse occurs at a time when voluntary prayer is prohibited, the Hanafi ruling is to engage in supplication and remembrance rather than perform the voluntary eclipse prayer in that prohibited interval.
Kusuf is a voluntary prayer, so it does not become an exception equivalent to an obligatory prayer.
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Eclipse Prayers: Solar and Lunar Rulings
If an eclipse occurs at a time when voluntary prayer is prohibited, the Hanafi ruling is to engage in supplication and remembrance rather than perform the voluntary eclipse prayer in that prohibited interval.
Kusuf is a voluntary prayer, so it does not become an exception equivalent to an obligatory prayer.