MS Quick Step Settings folder

I have an Office 365 / Exchange account which is sending certain emails into a folder called ‘Quick Step Settings’. Office 365 has created this folder and yet it is not visible in Outlook for Mac nor in Outlook in the Office 365 web page. It is not visible in Apple Mail either. It is however visible in Airmail3 and but for this the emails that are being sent to it would be entirely lost to me.

Any ideas as to what’s causing this and how on earth can I stop it.

One clue is that the emails which end up there all conform to an Apple Mail rule which contains a specific word.