Microservice MSCallGraph: a call is recorded more than twice

When explaining rpcid in the MSCallGraph dataset, README says “Note that, the call via remote invocation is recorded twice with the same rpcID in the UM and DM independently.” However, within the same trace (i.e. the traceid is the same), we found more than two occurrences of the same rpcid. Does it mean that the same rpc is sampled multiple times? Or does it mean different calls? (Also, many of those have rpctype mc, which means the DM is Memcached.) Thank you!