gen_random_uuid() creates a different UUID in each node of a replicated PostgreSQL environment.
This has been reported for mod-configuration and Pgpool-II replication in #sys-ops on Slack yesterday. From the Pgpool-II manual:
https://www.pgpool.net/docs/latest/en/html/restrictions.html

Functions, etc. In Native Replication mode

There is no guarantee that any data provided using a context-dependent mechanism (e.g. random number, transaction ID, OID, SERIAL, sequence), will be replicated correctly on multiple backends. For SERIAL, enabling insert_lock will help replicating data. insert_lock also helps SELECT setval() and SELECT nextval().

mod-configuration is special in that it lets the database create a new UUID that always overwrites any provided UUID for the primary key _id:

https://github.com/folio-org/mod-configuration/blob/v5.0.1/mod-configuration-server/src/main/java/org/folio/rest/impl/ConfigAPI.java#L159
https://github.com/folio-org/mod-configuration/blob/v5.0.1/mod-configuration-server/src/main/resources/templates/db_scripts/schema.json#L14-L15
https://github.com/folio-org/raml-module-builder/blob/v23.11.0/domain-models-runtime/src/main/resources/templates/db_scripts/main.ftl#L53

Most other modules never overwrite a primary key UUID _id provided by the caller of the POST API. And if no such primary key is provided they create a new one in Java code so that all replicated nodes receive the same _id. The suggested implementation in PgUtil.post also works this way:
https://github.com/folio-org/raml-module-builder/blob/v23.11.0/domain-models-runtime/src/main/java/org/folio/rest/persist/PgUtil.java#L358
https://github.com/folio-org/raml-module-builder/blob/v23.11.0/domain-models-runtime/src/main/java/org/folio/rest/persist/PgUtil.java#L305

How to fix:

• Add a section to RMB README.md how and why to generate UUIDs in Java.

• Fail with a error message pointing to that section when schema.json contains "generateId": true or "generateId": false so that all modules remove it when updating RMB. https://github.com/folio-org/raml-module-builder/tree/v23.11.0#the-post-tenant-api

• Remove the "generateId" support from schema.json tenant API: https://github.com/folio-org/raml-module-builder/blob/v23.11.0/domain-models-runtime/src/main/resources/templates/db_scripts/main.ftl#L53

• Do the same for "populateJsonWithId" as described in RMB-346. RMB-347 and RMB-346 should be implemented at the same time.

• No longer "CREATE EXTENSION pgcrypto" to fail any gen_random_uuid() usage.

If there is a consensus about https://folio-org.atlassian.net/browse/RMB-277 (default name for primary key name) that should also be implemented at the same time (= removing the schema.json option "pkColumnName").