Split not working with IF keywords inside BEGIN...END block

Describe the bug
sqlparse.split behaves incorrectly when IF keyword is present inside a BEGIN...END block

To Reproduce
An SQL statement passed to the split function

CREATE TASK t1 AS
BEGIN
    CREATE OR REPLACE TABLE temp1;
    DROP TABLE IF EXISTS temp1;
END;
EXECUTE TASK t1;

should result as two statements: CREATE TASK...END; and EXECUTE TASK t1;
But is resulting as a single statement

However, this issue is resolved as soon as the IF keyword is removed. For example,

CREATE TASK t1 AS
BEGIN
    CREATE OR REPLACE TABLE temp1;
    DROP TABLE temp1;
END;
EXECUTE TASK t1;

is working fine

Versions (please complete the following information):

Additional context
This statement is used in Snowflake DB

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