System-versioned table creates history row although UPDATE does not change row values

I observed that a system-versioned table creates a new history version even when an UPDATE statement does not modify any column value.

According to the MariaDB documentation:

“System-versioned tables store the history of all changes”

Source: https://mariadb.com/docs/server/reference/sql-structure/temporal-tables/system-versioned-tables/

In the following example, the UPDATE statement does not change the row values:

CREATE TABLE t1 (

  x INT UNIQUE,

  y INT

) WITH SYSTEM VERSIONING;

INSERT INTO t1 (x, y) VALUES (1, 1);

UPDATE t1

SET x = 1;

SELECT *, ROW_START, ROW_END

FROM t1

FOR SYSTEM_TIME ALL;

Expected result

Only one row should exist in history because no data values changed.

Actual result

Two versions are returned.

Although no column value changed, a new history version was created.

Question

Is this behavior intended?

If yes, the documentation may need clarification because it currently refers to storing the history of “changes”, while this behavior appears to version every UPDATE statement regardless of whether row values changed.