The affixes ktvā , kta and ktvātu get the iṭ augment after the root lubh (tudādigaṇaḥ (6th Conjugation)) when meaning 'entangled of confused'.,
As लुभित्वा and लोभित्वा, विलुभिताः केशाः, विलुभितः सीमन्तः, विलुभितानि पदानि ॥ विमोहनं = आकुलीकरणं ॥ By 7.2.48 लुभ would have optionally caused इट् to come before ktva, and then by 7.2.15 the Nishtha would never have been सेट् ॥ Hence this sutra. Why do we say when meaning 'to entangle'? See लुब्धः वृषलः = शीतेन पीडितः, ॥ लुभ् 'to be greedy' (Divadi 128) is not governed by this rule, but by 7.2.48. As लुब्ध्वा or लोभित्वा and लुभित्वा 1.2.26 ॥,