Duplicate key value violates unique constraint "conf_fie_pk" on Docker start up

[Gold]

Mahara version: 21.04dev
OS: dockerized ubuntu:bionic
DB: Postgres (Docker image postgres:9.5)

When *restarting* a docker instance we are seeing this a lot. It appears to be related to "_cron_lock_*" columns.

mahara-db | ERROR: duplicate key value violates unique constraint "conf_fie_pk"
mahara-db | DETAIL: Key (field)=(_cron_lock_auth_saml_auth_saml_refresh_cron) already exists.
mahara-db | STATEMENT: INSERT INTO "config" ("field", "value") VALUES ( $1, $2)
mahara-db | ERROR: duplicate key value violates unique constraint "conf_fie_pk"
mahara-db | DETAIL: Key (field)=(_cron_lock_auth_saml_auth_saml_refresh_cron) already exists.
mahara-db | STATEMENT: INSERT INTO "config" ("field", "value") VALUES ( $1, $2)