lcb_respping_result_scope segfaults if no scope

Trying to build the result for Ping and when I call (from rust)

lcb_respping_result_scope(ping_res, i, &mut scope_ptr, &mut scope_len);

for a non KV service then I see a SIGSEGV occur. I expected my scope_ptr value to be null and scope_len to be 0 if there was no scope for this index.