Hi,
As far as I could see this doesn't currently affect anything in the code but there's a pointer dereference here:
https://github.com/bitcoin-core/secp256k1/blob/master/src/ecmult_impl.h#L398

and only a few lines afterwards we check if it's not null
https://github.com/bitcoin-core/secp256k1/blob/master/src/ecmult_impl.h#L406