Confirmed this morning that the engineering team is investigating.
@Connor_Finlayson - your ticket was the catalyst for this. 
Thank you again for sending all those details over.
Totally missed this! Yes, I am using the “add row” action
I am facing same kind of issue : add a row to user table when refresh one specific value disappears.
Do you have solved those issues ?
Can you send us some screenshots on your setup, or a video?