Incorrect row number upon INSERT .. SELECT from the same table: rows are counted twice

create or replace table t (a tinyint);

insert into t values (1),(100);

insert into t select a*2 from t;

MariaDB [test]> insert into t select a*2 from t;

ERROR 1264 (22003): Out of range value for column 'a' at row 4

MariaDB [test]> create or replace table tmp select * from t;

Query OK, 2 rows affected (0.044 sec)

Records: 2  Duplicates: 0  Warnings: 0

MariaDB [test]> insert into t select a*2 from tmp;

ERROR 1264 (22003): Out of range value for column 'a' at row 2