MySQL error 1674 even when binlog is set to ROW
ALTER TABLE statements are still replicated as statements. Even with binlog_format=ROW this will be requiring the existing table populate the existing rows with an AccessCode.

I recommend:

ALTER TABLE Account ADD AccessCode binary(16) NOT NULL;
UPDATE Account SET AccessCode = UUID_TO_BIN(UUID());


This manual page says that non-determinstic default functions on columns may produce a warning or error (CURRENT_TIMESTAMP was an exception).

I'm not sure you can create this, even on the master after executing SET SESSION sql_log_bin=0; ALTER TABLE Account Alter AccessCode SET DEFAULT (UUID_TO_BIN(UUID())), I tried MySQL-8.0 however your version may differ.