Regex Capture does not keep durable variables

I am trying Postman Flows, but the Regex Capture block behaves unexpectedly. I have created the minimal reproducible example to show the problem:

In the first “Create Durables” block, I set a durable variable myDurableVar that is forgotten after the “Regex Capture” block. I thought this is a bug because all the other blocks I have tried keep the durable variables after execution.