BUG #18756: Postgres corruption

The following bug has been logged on the website:

Bug reference: 18756
Logged by: Tal Moshe
Email address: talmoshe24(at)gmail(dot)com
PostgreSQL version: 14.13
Operating system: centos9
Description:

We saw a corruption in 3 different environments in one of the unique indexes
(named “npn”) in “files” table.
It seems as if not all the rows (that should be part of this index) in the
table are indexed, and therefore “duplicated” rows (rows that violates the
index constraint) are allowed to be inserted to DB.

The index is created using the following statement:
CREATE UNIQUE INDEX npn ON public.files USING btree (SNAPSHOT_ID,
PARENT_GUID_DEVICE, PARENT_GUID_VERSION, NAME) WHERE PARENT_GUID_DEVICE IS
NOT NULL;

In these environments Postgres v14.13 is used.