Account key is not triggering only accrual key posted

Hi,

In MM pricing procedure for a condition type both account key FRE and accrual key FR1 maintained, but system is posting at the time of GR and IR with accrual key only. Why system is not triggering account key FRE at all, Please through some light

When both keys will be triggered ?

GR

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Accrual key FR1 GL account credited

IR

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Accrual key FR1 GL account Debited