BUG #18475: pg_dump: "Error Segmentation fault"

The following bug has been logged on the website:

Bug reference:      18475
Logged by:          Philippe Loustaunau
Email address:      philippe.loustaunau@developpement-durable.gouv.fr
PostgreSQL version: 12.18
Operating system:   Ubuntu 20.04.1
Description:

We have in our services several PostgreSQL servers from the Ubuntu 20.04.1
distribution (PostgreSQL 12.18 on Ubuntu 20.04.1) 
We note that the backup actions of our databases including partitioned
tables cause a pg_dump error with the message "Segmentation error"
However, it has not yet been possible to reproduce it on a PostgreSQL 12
server under Windows. Servers running Ubuntu 18.04 with PostgreSQL 10 also
appear unaffected.
Backup command: pg_dump -U postgres -F c -C -c -w $base > ${target}. The
error persists when directory format is used instead of custom.
After tests, it turns out that excluding the partitioned table from the
backup eliminates the error.