The relay is a fault detector, and should only energise if the power is applied to the whole circuit, but K1 does not energise.
The problem the OP describes is that the contactor K1 is relatively slow to operate.
So, between power being applied and K1 actually energising to disconnect the fault relay, the much faster relay briefly activates and flags a fault condition when there is not actually one.
It is a "Race condition" problem with different parts of the circuit having different operating delays.
A genuine fault would be if eg. power is applied but K1 has not activated with a couple of hundred milliseconds.
An on-delay timer in place of the relay would prevent the brief false error state occurring.