If Event Tickets are purchased with a donation with a Subscription (definitely with Stripe), OR with PayPal Donations (one-time or subscription) + Events, GiveWP sends only the donation amount to the gateway. The donation confirmation step and donation in GiveWP shows that the full amount (donation + tickets) was charged, but only the donation amount is sent to PayPal Donations.
This happens for both recurring and one-time donations in PayPal, and only subscriptions (Stripe for sure)
The only workaround so far is to use a different gateway for one-time donations.