Featured item Post Image not displayed

We are on 10.1.10. We are Featuring a blog post in a group. The article shows up in the Featured Content Carousel but the post image does not. The Featured Content Carousel  widget is the default version. 

To add the image we go to the admin slide out panel and choose Manage Group > Featured Content and then select the item that is featured and Edit Feature. Under Poster Image we click Add or Change image and select the image to be used. The image initially shows up as a preview image and we Save. 

Coming back to the Edit Feature panel we find that the image is no longer there. We have the "broken image" icon in its place. 

I have looked that network traffic when the file is uploaded using Chrome Developer Tools. Everything there appears to have worked just fine with no network or HTTP errors. 

Looking in the Exceptions logs there is an exception. There was an error in preparing a resized image because a part of the path was not found. 

UnknownException: An error occurred when attempting to prepare a resized version of an image. ---> 
System.IO.DirectoryNotFoundException: Could not find a part of the path

I have looked at the filestore location in the exception and the directory referenced does exist and have the correct permissions. But the folder is empty.

I have checked the network traffic to see that the path specified when uploading is the one being referenced ... and it is. I went so far as to rename the empty directory in the filestore and attempted to add the image again. It recreated the directory that I renamed and that new directory is also empty.

And I can add that this group has one other Featured post which has an poster image added to it just a few days ago. That image displays correctly in the carousel and is stored in the filestore where it is expected to be. That was added a couple of weeks ago and there have been no software updates recently.

Any ideas as to why the image is not being stored would be most appreciated.