Hive account@steemchiller trying to decrease my delegation to a user on Steemworld, but getting this error:

10 assert_exception: Assert Exception delta >= min_update: Steem Power decrease is not enough of a difference. min_update: 203.334982 VESTS {"min":"203.334982 VESTS"} th_a steem_evaluator.cpp:2242 do_apply {"op":["delegate_vesting_shares",{"delegator":"dirkboy41","delegatee":"bigtx31","vesting_shares":"508337.483255 VESTS"}]} th_a database.cpp:2900 _apply_transaction {"trx":{"ref_block_num":22206,"ref_block_prefix":540944119,"expiration":"2018-05-30T21:41:27","operations":[["delegate_vesting_shares",{"delegator":"dirkboy41","delegatee":"bigtx31","vesting_shares":"508337.483255 VESTS"}]],"extensions":[],"signatures":["2079cc71f3464c2880f6723be62a7e8fd53a1d86b9b048504cb2cd6524a4773e2a650819b742724e36d3f60daec4f35ebc620ca78b7c834a085279cd26db4eb707"]}} th_a database.cpp:2904 _apply_transaction {"trx":{"ref_block_num":22206,"ref_block_prefix":540944119,"expiration":"2018-05-30T21:41:27","operations":[["delegate_vesting_shares",{"delegator":"dirkboy41","delegatee":"bigtx31","vesting_shares":"508337.483255 VESTS"}]],"extensions":[],"signatures":["2079cc71f3464c2880f6723be62a7e8fd53a1d86b9b048504cb2cd6524a4773e2a650819b742724e36d3f60daec4f35ebc620ca78b7c834a085279cd26db4eb707"]}} th_a database.cpp:660 push_transaction {"call.method":"call","call.params":[3,"broadcast_transaction_synchronous",[{"ref_block_num":22206,"ref_block_prefix":540944119,"expiration":"2018-05-30T21:41:27","operations":[["delegate_vesting_shares",{"delegator":"dirkboy41","delegatee":"bigtx31","vesting_shares":"508337.483255 VESTS"}]],"extensions":[],"signatures":["2079cc71f3464c2880f6723be62a7e8fd53a1d86b9b048504cb2cd6524a4773e2a650819b742724e36d3f60daec4f35ebc620ca78b7c834a085279cd26db4eb707"]}]]} th_a websocket_api.cpp:124 on_message (see err.payload for the full error payload)
Ok

Any ideas?