strange behavior of WAL files

HI,

We have a centos 6 enviornment where postgres 9.6 is running on it.

We have strange behavior of WAL files of pg_xlog directory

As we have set archive_command to archive WAL files at different
location and the archive_command is working fine.

So strange behavior is :

We have a WAL file say for example "00000001000036CD000000E2" of
01.06.2021 (1st June 2021) that is getting archive successfully at the
archive location and once it is archived, this file with same name
(00000001000036CD000000E2) is getting generated with the latest
timestamp (as today is 04.06.2021).and all old WAL files are behaving
in same manner.

Old WAL files get archived and once it get archived they get generated
with the same name with latest timestamp.

So please help me in telling why such kind of behavior is occurring.

So why this kind of behavior is happening.

the total number of files in pg_xlog directory is around 4016.

Note: There is no replication configured on the server.

Regards,
Atul

Regards,
Atul