क्रियासमभिहार is repetition or excess (भृश). In the sense of repetition or excess and in present tense, the अच् (only once) हलादि धातुs have यङ्. For example, पच् पच् य - प् पच् य - पा पच् य (दीर्घो-अकितः) - पापच्यते. Note that पुनःजागृ doesn't result in यङ् since जागृ is not एकाच् (it has two अच्s). Note also that भृशं ईक्षते doesn't result in यङ् - since the धातु is not हलादि.