Help with #Flow

Hi guys! 

I am new with the flow and stuck with it, I need your help to figure it out!

I have requirements:

1. A task should be created from the contact if our custom field "Date to reconnect" changes and the previous task should be deleted.

2. The "assign To" field on the task should be populated with the Assign BDR value from the contact of this field if it is not blank, but if the field is blank - then the "Assign To" field should be filled in with the contact Owner value. - and I have a problem with this part.

3. Email should be sent 3 days before the new Date to Reconnect.

Here is my suggestions.

First, I created a simple flow with 1+3 requirements, and the Assign To field was populated with the Contact Owner field, and it is working perfectly. 

 But I need to add a condition - The "assign To" field on task should be populated with the Assign BDR value from the contact of this field if it is not blank, but if the field is blank - then the "Assign To" field should be filled in with the contact Owner value.

and I add a decision element and create to the path if the contact has Assign BDR - assign them; if not assign the contact owner 

But in this case, flow creates a Fault path, and I cannot change it for a regular one, and flow does not work properly. That is why I create another decision element the same as before but put it after delete record element

But it this case I receive an Error, during the testing, In the path  - when the task creates with owner ID value, the Error that "Assign to" cannot be blank, and I do not understand why this error appears because Assign To is not blank.

Here is the flow inside 

I feel like somehow exists some simple way just to add a condition that if "Assign BDR" on Contact is not blank - take it to the "Assign To" field on Task, but if blank - take the contact owner. But I cant to figure out how this is set up in a simple way.

Please help me with that :) 

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