It happens almost every year. Due to the inclusion of PSP and FSP in boys' preferences, their preference number for Postal is below than most of the girls' preferences. Thats why girls with lower merit number get allocated in Postal and Boys with higher merit do not get it.
Told by ED person when asked from him after our allocations were announced.

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"And I thought about how he knew to put the 'pursuit' in there, like no one can actually have happiness. We can only pursue it."