Cache corruption issue

Something is causing the Credits APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways. results cache to be corrupted – I’m assuming a job somewhere is triggering it, but I have no way to track it down.

Are you able to find out what is writing to the props-4.9 key in the core-credits-api cache group?


Incorrect Return-Path on mail from

The Return-Path is currently set to, which may be contributing to emails getting marked as spam for some recipients. Relevant headers from one such email:

Received-SPF: Neutral ( is neither permitted nor denied by domain of ) client-ip:
    spf=neutral ( is neither permitted nor denied by domain of
Return-Path: <>
Date: Fri, 20 Oct 2017 12:20:46 +0000
From: WordPress <>

This same issue has come up before (1, 2), and it appears that the Return-Path was changed at that time, so perhaps it was somehow reverted at a later date?

cc @stankea