Does Salesforce IP session locking impact FinDock?

The short answer is YES. Here's why...

Salesforce security settings include a range of Session Settings to help harden org security. One method is to lock authorized connections to a specific IP address. This is enabled with the Lock sessions to the IP address from which they originated setting.

FinDock uses a service architecture that leverages dynamic IP addressing. PSP notification handling and FinDock Giving Pages, for instance, rely on tokenization across multiple IP addresses. If sessions are locked to a specific IP, incoming notifications get stuck (and don't arrive in Salesforce). Redirecting and similar aspects of Giving Pages will also fail.