Does a sandbox refresh or renewal impact FinDock?

Yes. When you create a new sandbox or refresh your existing sandbox with FinDock, you should carefully check the FinDock configuration in the new org.

We recommended the following:

Check that the initial Remote Site Setting is created
Delete any production targets pointing to live endpoints. This includes ProcessingHub targets and merchant account settings in payment extensions.
Check that a default Source Connector is selected and the Heart Beat Job is scheduled under Core general settings.
Check that there is a successful (working) connection to WebHub and to ProcessingHub.
Make sure you have a Chatter group for file exchanges.

Keep in mind potentially sensitive customer and payment data (e.g. bank account numbers and credit card tokens from PSPs) when working with sandboxes. For further information, please refer to Salesforce Sandbox Types and Templates.