Is a valid marriage contract required for Ihsan?

Supporting text

Abu Thur held that Ihsan is established by intercourse in a void marriage contract, a view attributed also to Al-Layth and Al-Awza'i. Their rationale is that valid and void marriages share most legal consequences, such as the obligation of Mahr (dower), 'Iddah (waiting period), prohibition regarding the stepdaughter and the wife's mother, and filiation of offspring. The counter-argument is that this intercourse occurred outside legal ownership, thus lacking Ihsan, similar to accidental intercourse, and the shared rulings cited are established by the intercourse itself, not exclusively by the valid marriage contract.