There is copy&paste error in libgcrypt ecc-curves.c _gcry_ecc_get_mpi at line 1209:

https://dev.gnupg.org/source/libgcrypt/browse/master/cipher/ecc-curves.c;0f2c6ce2c9504c6df435463243edaa669e57b109$1209

ecc->Q->y should be tested instead of ecc->G->y