There is guṇa in the liṭ (Perfect Tense) of 1. ṛcch 2. ṝ and roots ending in long ṝ,
As आनर्च्छ, आनर्च्छतुः, आनर्च्छुः from ऋच्छ्, आर, आरतुः, आरुः from ऋ, and नि चकरतुः, नि चकरुः, नि जगरतुः, नि जगरुः from कॄ and गॄ ॥ ऋच्छ् not having a light vowel in the penultimate, would not have received guna by 7.3.86, this sutra ordains it; roots in long ॠ never received guna, but इर् substitution; this ordains guna. The Vriddhi of 7.2.115 supersedes this rule, within its own jurisdiction, a prior superseding the posterior: as निचकार, नि जगार ॥,