On the security of Fiat-Shamir (FS) type signatures, some negative circumstantial evidences were given in the non-programmable random oracle model (NPROM). Fischlin and Fleischhacker first showed an impossibility for specific FS-type signatures via a single-instance reduction. In ISC 2015, Fukumitsu and Hasegawa found another conditions to prove such an impossibility, however their result requires a strong condition on a reduction, i.e. a key-preserving reduction. In this paper, we focus on a non-key-preserving reduction, and then we show that an FS-type signature cannot be proven to be secure in the NPROM via a sequentially multi-instance reduction from the security of the underlying ID scheme. Our result can be interpreted as a generalization of the two impossibility results introduced above. By applying our impossibility result, the security incompatibility between the DL assumption and the security of the Schnorr signature in the NPROM via a sequentially multi-instance reduction can be shown. Our incompatibility result means that the security of the Schnorr signature is not likely to be proven in the NPROM.