If you were not using Pi-Hole, how would you be resolving DNS? Going straight to Google would be no different. They would see these PTR queries and more (i.e. regular reverse lookups not mapped in hosts or leases files).
This feature is unchanged in dnsmasq for at least the last seven years. It's not a Pi-Hole issue.
However, note that a new feature of Pi-Hole V4.1 did allow you to see this traffic leaving your network. Previously you did not see the traffic, so the new feature provided this information. In that regard, it did expose something, giving you greater visibility to your DNS traffic.