Similar past-tense alifs do not guarantee identical present-tense patterns.
PerfectImperfectJussiveType
قَالَيَقُولُلَمْ يَقُلْHollow-wāw
بَاعَيَبِيعُلَمْ يَبِعْHollow-yāʾ
خَافَيَخَافُلَمْ يَخَفْHollow-wāw
It is wrong to assume that because خَافَ is hollow-wāw, its imperfect must be *yakhūfu*. The individual lexical pattern is indispensable: خَافَ يَخَافُ.
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Advanced Sarf Application: Ambiguous Forms, Weak-Letter Reasoning and Error Correction
Similar past-tense alifs do not guarantee identical present-tense patterns.
PerfectImperfectJussiveType
قَالَيَقُولُلَمْ يَقُلْHollow-wāw
بَاعَيَبِيعُلَمْ يَبِعْHollow-yāʾ
خَافَيَخَافُلَمْ يَخَفْHollow-wāw
It is wrong to assume that because خَافَ is hollow-wāw, its imperfect must be *yakhūfu*. The individual lexical pattern is indispensable: خَافَ يَخَافُ.