Auto Increment is increasing while using INSERT IGNORE INTO and UNIQUE index

I am attaching test DB with simulated problem:
DB.sql

How to simulate properly:
A) import DB
B) run 5 times this query:
INSERT IGNORE INTO `aaa` SET `c` = 'cz', `b` = 1, `a` = 8;
C) auto increment will be increased for 5 (unwanted behaviour - there is no reason to increase auto increment)

We have now tens of millions unwanted auto increment increased.