Index (primary key) corrupt?

Hello,

When doing a pg_dump of one of our databases one of the tables primary keys doesn’t get exported. Pg_dump just skips this index, without any warning whatsoever (verbose mode was used to doublecheck).

When doing a REINDEX the issue is fixed.

As this seems to me to be some form of index corruption, I tried using amcheck (bt_index_check and bt_index_parent_check) to verify for corruption but both resulted with no issues (the index is a btree).

I would expect the corruption to show up when using amcheck, am I hitting some kind of bug here?

Are there any other ways to doublecheck for corruption (without enabling checksum upfront)?

This concerns a PostgreSQL version 15 btw.

Thanks!