IPv4 or IPv6 localhost standardization

Every now and then we get a customer with intermittent connection failures to the upstream service because DNS starts resolving localhost to the IPv6 localhost. Is there any benefit to using IPv6 localhost? If not, then I think it would prevent many issues if we were to - by default - bind all of our services to 127.0.0.1 instead of localhost, and use the same for connections.

One good example of this problem is contained within this ticket: https://gitlab.zendesk.com/agent/tickets/161006 (internal GitLab use only)