Can you try get_bulk_payments?
If you are compiling yourself, you can try replacing the if here: https://github.com/monero-project/bitmonero/blob/master/src/wallet/wallet_rpc_server.cpp#L472
With the one here (the whole statement): https://github.com/monero-project/bitmonero/blob/master/src/wallet/wallet_rpc_server.cpp#L537
It looks like an oversight at first glance.
Edit: you can also probably 0-pad your 16 char one to get to 64.
Edit2: https://github.com/monero-project/bitmonero/commit/d0f011d873b51e243e767fc5f485374f00600225
Thanks for reporting.