Inconsistent results when “using timestamp” on YugabyteDB YCQL - yugabytedb

Question

[Question posted by a user on YugabyteDB Community Slack]
I'm trying to upsert, delete and upsert the same record using using timestamp syntax. The first upsert and delete are successful. After I delete the record, if I upsert the same record again, the update status is true, but the select statement is not showing the row.
ycqlsh:test> CREATE TABLE todo ( id int, seq int, task text, status boolean, primary key (id, seq) );
ycqlsh:test> insert into todo(id, seq, task, status) values(1, 1, 'sample', false);
ycqlsh:test> insert into todo(id, seq, task, status) values(1, 2, 'sample2', false);
ycqlsh:test> select * from todo;
id | seq | task | status
----+-----+---------+--------
1 | 1 | sample | False
1 | 2 | sample2 | False
(2 rows)
ycqlsh:test> UPDATE todo using timestamp 1000 SET status = false, task='sample3' WHERE id=1 and seq=3 returns status as row;
[applied] | [message] | id | seq | task | status
-----------+-----------+------+------+------+--------
True | null | null | null | null | null
ycqlsh:test> select * from todo;
id | seq | task | status
----+-----+---------+--------
1 | 1 | sample | False
1 | 2 | sample2 | False
1 | 3 | sample3 | False
(3 rows)
ycqlsh:test> delete from todo WHERE id=1 and seq=3;
ycqlsh:test> select * from todo;
id | seq | task | status
----+-----+---------+--------
1 | 1 | sample | False
1 | 2 | sample2 | False
(2 rows)
ycqlsh:test> UPDATE todo using timestamp 2000 SET status = false, task='sample3' WHERE id=1 and seq=3 returns status as row;
[applied] | [message] | id | seq | task | status
-----------+-----------+------+------+------+--------
True | null | null | null | null | null
ycqlsh:test> select * from todo;
id | seq | task | status
----+-----+---------+--------
1 | 1 | sample | False
1 | 2 | sample2 | False

Answer 1

This is because you use DELETE without USING. To reintroduce the row back into the table, you have to use UPDATE without USING TIMESTAMP.
The correct usage should have been:
delete from todo USING TIMESTAMP 1000 id=1 and seq=3;
If you want DELETE without the use of USING timestamp... then you should use timestamp values that are actually close to physical time in microseconds since epoch rather than numbers like 1000 or 2000.