I assume this is the 8BA version of the 2100 Holley series (old model 94). I don't know the quality of the seals, gaskets, or power valves used in these new units but even the old originals can leak like a sieve if there is a problem. Modern fuels with added alcohol are not kind to soft parts but some parts are better quality than others.
Has this carb been in service for this time period or not? It might be easier to just rebuild it than mess with an out of warranty situation with a vendor. Charley NY and others could do you better than sending it to the vendor and you will have some piece of mind working with a reputable rebuilder too. If your so inclined, you can get a good quality kit and do it yourself.