@Alex Edelstein 

1. We have a process that executes after a Case is updated.  It's purpose is to update the Case's Contact record.
2. The Contact object's Account field has a Lookup Filter.  The filter was added AFTER some records were created with values that would now fail with the current filter.
3. The Case record is updated, executing the Process.
4. The Process attempts to update a custom field on the Case's parent Contact.
5. The Process fails with the error:   FIELD_FILTER_VALIDATION_EXCEPTION .
6. If the Contact record is corrected or if the Lookup Filter is altered then the Process works as expected.
7. Is there a method to bulletproof the process to avoid the user seeing the Fault Error Message?
8. With Flow we have fault handling.  I am hoping I could update the Contact via the Flow, and if it should fail due to the same error, the fault handling would handle it better such as executing a Core Action.
9. My question is if the Process calls the Flow, and then Flow's Fault Handler executes, would the Process still generate the same error to the end-user?
10. Or do you have any other suggestions?

@Salesforce Process Builder @Jennifer (Jen) Lee @RAKESH GUPTA @Meighan Brodkey @Jake Faris @Shannon Hale